Solid polyglycol-based biocompatible pre-formulation

ABSTRACT

Provided herein are pre-formulations forming a biocompatible hydrogel polymer comprising at least one nucleophilic compound or monomer unit, at least one electrophilic compound or monomer unit, and optionally a therapeutic agent and/or viscosity enhancer. In some embodiments, the biocompatible hydrogel polymer covers a wound in a mammal and adheres to the surrounding skin tissue. In other embodiments, the hydrogel polymer is delivered into a joint space to treat joint disease or navicular disease.

CROSS-REFERENCE

This application claims the benefit of U.S. Provisional Application No.61/785,477, filed Mar. 14, 2013, which application is incorporatedherein by reference.

BACKGROUND OF THE INVENTION

During surgery in animals such as dogs, cats and horses etc.postsurgical and other wounds need to be sealed. Many commerciallyavailable bandages are scratched away or pulled off by animals and aredislodged from the location resulting in serious risk of infections. Itis estimated that over 90% of the animals are back a second time afterthe surgery due to wound infection.

Animals also commonly develop arthritis in small “low motion” joints.These joints can cause a significant of pain causing lameness and ownerdistress. The most common treatment for this issue is an intra-articularjoint injection of a corticosteroid.

Navicular disease is degeneration of the distal sesamoid bone in thehorse. This disease causes millions of dollars lost in the equinecommunity.

SUMMARY OF THE INVENTION

In one aspect, provided herein is a solid polyglycol-based, fullysynthetic, pre-formulation, comprising at least one solid first compoundcomprising more than two nucleophilic groups; and at least one solidsecond compound comprising more than two electrophilic groups; whereinthe solid polyglycol-based, fully synthetic, pre-formulation polymerizesand/or gels to form a polyglycol-based, fully synthetic, biocompatiblehydrogel polymer in after addition of a liquid component. In someembodiments, the solid polyglycol-based, fully synthetic,pre-formulation, further comprises a solid buffer component. In someembodiments, the liquid component comprises water, saline, a buffer, atherapeutic agent or a combination thereof. In certain embodiments, theliquid component comprises water. In certain embodiments, the liquidcomponent comprises saline. In certain embodiments, the liquid componentcomprises a buffer. In certain embodiments, the liquid componentcomprises a therapeutic agent. In some embodiments, thepolyglycol-based, fully synthetic, biocompatible hydrogel polymer atleast partially adheres to a target site.

In certain embodiments, the solid polyglycol-based, fully synthetic,pre-formulation further comprises a viscosity enhancer. In someembodiments, the viscosity enhancer is selected fromhydroxyethylcellulose, hydroxypropylmethylcellulose, methylcellulose,polyvinyl alcohol, or polyvinylpyrrolidone.

In some embodiments, the nucleophilic group comprises a thiol or aminogroup. In certain embodiments, the nucleophilic group comprises an aminogroup. In some embodiments, the solid first compound is a polyolderivative. In some embodiments, solid first compound is atrimethylolpropane, diglycerol, pentaerythritol, sorbitol, hexaglycerol,tripentaerythritol, or polyglycerol derivative. In certain embodiments,the solid first compound is a trimethylolpropane, pentaerythritol,hexaglycerol, or tripentaerythritol derivative. In some embodiments, thesolid first compound is a pentaerythritol or hexaglycerol derivative. Incertain embodiments, the solid first compound is selected from the groupconsisting of ethoxylated pentaerythritol ethylamine ether, ethoxylatedpentaerythritol propylamine ether, ethoxylated pentaerythritol aminoacetate, ethoxylated hexaglycerol ethylamine ether, ethoxylatedhexaglycerol propylamine ether, and ethoxylated hexaglycerol aminoacetate. In some embodiments, the solid first compound is a MULTIARM(5k-50k) polyol derivative comprising polyglycol subunits and more thantwo nucleophilic groups. In some embodiments, MULTIARM is 3ARM, 4ARM,6ARM, 8ARM, 10ARM, 12ARM. In some embodiments, MULTIARM is 4ARM or 8ARM.In some embodiments, the solid first compound is a MULTIARM-(5-50k)-SH,a MULTIARM-(5-50k)-NH2, a MULTIARM-(5-50k)-AA, or a combination thereof.In certain embodiments, the solid first compound is 4ARM-(5k-50k)-SH,4ARM-(5k-50k)-NH2, 4ARM-(5k-50k)-AA, 8ARM-(5k-50k)-NH2,8ARM-(5k-50k)-AA, or a combination thereof. In some embodiments, thesolid first compound is 4ARM-5k-SH, 4ARM-2k-NH2, 4ARM-5k-NH2,8ARM-20k-NH2, 4ARM-20k-AA, 8ARM-20k-AA, or a combination thereof.

In some embodiments, the solid first compound further comprises a solidsecond first compound comprising more than two nucleophilic groups. Insome embodiments, the solid first compound further comprises a solidsecond first compound that is a MULTIARM-(5k-50k) polyol derivativecomprising polyglycol subunits and more than two nucleophilic groups. Insome embodiments, the solid second first compound isMULTIARM-(5-50k)-SH, MULTIARM-(5k-50k)-NH2, MULTIARM-(5k-50k)-AA. Insome embodiments, the solid first compound is water soluble.

In certain embodiments, the electrophilic group is an epoxide,N-succinimidyl succinate, N-succinimidyl glutarate, N-succinimidylsuccinamide or N-succinimidyl glutaramide. In some embodiments, theelectrophilic group is N-succinimidyl glutaramide. In some embodiments,the solid second compound is a polyol derivative. In certainembodiments, the second compound is a trimethylolpropane, diglycerol,pentaerythritol, sorbitol, hexaglycerol, tripentaerythritol, orpolyglycerol derivative. In some embodiments, the second compound is atrimethylolpropane, pentaerythritol, or hexaglycerol derivative. Incertain embodiments, the solid second compound is selected from thegroup consisting of ethoxylated pentaerythritol succinimidyl succinate,ethoxylated pentaerythritol succinimidyl glutarate, ethoxylatedpentaerythritol succinimidyl glutaramide, ethoxylated hexaglycerolsuccinimidyl succinate, ethoxylated hexaglycerol succinimidyl glutarate,and ethoxylated hexaglycerol succinimidyl glutaramide. In someembodiments, the solid second compound is a MULTIARM-(5k-50k) polyolderivative comprising polyglycol subunits and more than twoelectrophilic groups. In certain embodiments, the solid second compoundis a MULTIARM-(5-50k)-SG, MULTIARM-(5-50k)-SGA, MULTIARM-(5-50k)-SS,MULTIARM-(5-50k)-SSA, or a combination thereof. In certain embodiments,the solid second compound is 4ARM-(5-50k)-SG, 4ARM-(5-50k)-SGA,4ARM-(5-50k)-SS, 8ARM-(5-50k)-SG, 8ARM-(5-50k)-SGA, 8ARM-(5-50k)-SS, ora combination thereof. In some embodiments, the solid second compound is4ARM-10k-SG, 8ARM-15k-SG, 4ARM-20k-SGA, 4ARM-10k-SS, or a combinationthereof.

In some embodiments, the solid first compound is a MULTIARM-(5-50k)-SH,a MULTIARM-(5-50k)-NH2, a MULTIARM-(5-50k)-AA, or a combination thereof,and the solid second compound is a MULTIARM-(5-50k)-SG, aMULTIARM-(5-50k)-SGA, a MULTIARM-(5-50k)-SS, or a combination thereof.In other embodiments, the solid first compound is 4ARM-5k-SH,4ARM-2k-NH2, 4ARM-5k-NH2, 8ARM-20k-NH2, 4ARM-20k-AA, 8ARM-20k-AA, or acombination thereof, and the solid second compound is 4ARM-10k-SG,8ARM-15k-SG, 4ARM-20k-SGA, 4ARM-10k-SS, or a combination thereof. Incertain embodiments, the solid first compound is 8ARM-20k-NH2 and/or8ARM-20k-AA, and the solid second compound is 4ARM-20k-SGA. In someembodiments, the solid second compound is water soluble.

In some embodiments, the solid polyglycol-based, fully synthetic,pre-formulation gels at a predetermined time to form thepolyglycol-based, fully synthetic, biocompatible hydrogel polymer. Incertain embodiments, the polyglycol-based, fully synthetic,biocompatible hydrogel polymer is bioabsorbable. In some embodiments,the polyglycol-based, fully synthetic, biocompatible hydrogel polymer isbioabsorbed within about 1 to 70 days. In certain embodiments, thepolyglycol-based, fully synthetic, biocompatible hydrogel polymer issubstantially non-bioabsorbable.

In some embodiments, the solid polyglycol-based, fully synthetic,pre-formulation further comprises a radiopaque material or apharmaceutically acceptable dye. In certain embodiments, the radiopaquematerial is selected from sodium iodide, barium sulfate, tantalum,Visipaque®, Omnipaque®, or Hypaque®, or combinations thereof.

In some embodiments, the solid polyglycol-based, fully synthetic,pre-formulation further comprises one or more therapeutic agents. Incertain embodiments, the therapeutic agent is an antibacterial agent, anantifungal agent, an immunosuppressant agent, an anti-inflammatoryagent, a bisphosphonate, gallium nitrate, stem cells, an antisepticagent, or a lubricity agent. In some embodiments, the anti-inflammatoryagent is a corticosteroid or a TNF-α inhibitor. In some embodiments, theanti-inflammatory agent is a corticosteroid. In certain embodiments, thecorticosteroid is trimacinolone or methylprednisolone. In someembodiments, the therapeutic agent is an antiseptic agent. In certainembodiments, the antiseptic agent is chlorhexidine. In some embodiments,the therapeutic agent is a lubricity agent. In certain embodiments, thelubricity agent is hyaluronic acid. In some embodiments, the therapeuticagent is released from the polyglycol-based, fully synthetic,biocompatible hydrogel polymer through diffusion, osmosis, degradationof the polyglycol-based, fully synthetic, biocompatible hydrogelpolymer, or any combination thereof. In certain embodiments, thetherapeutic agent is initially released from the polyglycol-based, fullysynthetic, biocompatible hydrogel polymer through diffusion and laterreleased through degradation of the polyglycol-based, fully synthetic,biocompatible hydrogel polymer. In some embodiments, the therapeuticagent is substantially released from the polyglycol-based, fullysynthetic, biocompatible hydrogel polymer within 180 days. In certainembodiments, the therapeutic agent is substantially released from thepolyglycol-based, fully synthetic, biocompatible hydrogel polymer within14 days. In some embodiments, the therapeutic agent is substantiallyreleased from the polyglycol-based, fully synthetic, biocompatiblehydrogel polymer within 24 hours. In certain embodiments, thetherapeutic agent is substantially released from the polyglycol-based,fully synthetic, biocompatible hydrogel polymer within one hour. In someembodiments, the first compound and the second compound do not reactwith the therapeutic agent during formation of the polyglycol-based,fully synthetic, biocompatible hydrogel polymer. In certain embodiments,the polyglycol-based, fully synthetic, biocompatible hydrogel polymerinteracts with the therapeutic agent, and wherein more than 10% of thetherapeutic agent is released through degradation of thepolyglycol-based, fully synthetic, biocompatible hydrogel polymer. Insome embodiments, more than 30% of the therapeutic agent is releasedthrough degradation of the polyglycol-based, fully synthetic,biocompatible hydrogel polymer. In certain embodiments, thepolyglycol-based, fully synthetic, biocompatible hydrogel polymerinteracts with the therapeutic agent by forming covalent bonds betweenthe polyglycol-based, fully synthetic, biocompatible hydrogel polymerand the therapeutic agent. In some embodiments, the polyglycol-based,fully synthetic, biocompatible hydrogel polymer interacts with thetherapeutic agent by forming a non-covalent bond between thepolyglycol-based, fully synthetic, biocompatible hydrogel polymer andthe therapeutic agent. In some embodiments, the therapeutic agent isreleased while the polyglycol-based, fully synthetic, biocompatiblehydrogel polymer degrades. In certain embodiments, the release of thetherapeutic agent is essentially inhibited until a time that thepolyglycol-based, fully synthetic, biocompatible hydrogel polymer startsto degrade. In some embodiments, the time the polyglycol-based, fullysynthetic, biocompatible hydrogel polymer starts to degrade is longerthe higher a degree of cross-linking of the polyglycol-based, fullysynthetic, biocompatible hydrogel polymer. In certain embodiments, thetime the polyglycol-based, fully synthetic, biocompatible hydrogelpolymer starts to degrade is shorter the higher a concentration of estergroups in the first or second compound.

In one aspect, provided herein is a method of treating wounds of amammal by delivering a liquid polyglycol-based, fully synthetic,biocompatible formulation formed by adding a liquid component to thesolid polyglycol-based, fully synthetic, pre-formulation to a targetsite of the wound of the mammal, wherein the liquid polyglycol-based,fully synthetic, biocompatible formulation gels at the target site ofthe wound to form a polyglycol-based, fully synthetic, biocompatiblehydrogel polymer. In another aspect, provided herein, is a method oftreating arthritis in a mammal by delivering a liquid polyglycol-based,fully synthetic, biocompatible formulation formed by adding a liquidcomponent to the solid polyglycol-based, fully synthetic,pre-formulation into a target site in a joint space, wherein the liquidpolyglycol-based, fully synthetic, biocompatible formulation gels at thetarget site in the joint space to form a polyglycol-based, fullysynthetic, biocompatible hydrogel polymer. In a further aspect, providedherein is a method of treating navicular disease in a horse bydelivering a liquid polyglycol-based, fully synthetic, biocompatibleformulation formed by adding a liquid component to the solidpolyglycol-based, fully synthetic, pre-formulation to a target site in ahoof of the horse, wherein the liquid polyglycol-based, fully synthetic,biocompatible formulation gels at the target site in the hoof of thehorse to form a polyglycol-based, fully synthetic, biocompatiblehydrogel polymer. In certain embodiments of methods described herein,the polyglycol-based, fully synthetic, biocompatible hydrogel polymercloses the wound. In some embodiments, the polyglycol-based, fullysynthetic, biocompatible hydrogel polymer covers the wound and adheresto surrounding skin. In some embodiments, the mammal is a human. Incertain embodiments, the mammal is an animal. In some embodiments, theanimal is a dog, cat, cow, pig, or horse.

In some embodiments, the polyglycol-based, fully synthetic,biocompatible hydrogel polymer of the synthetic, pre-formulation asdescribed herein.

In another aspect, provided herein is a polyglycol-based, fullysynthetic, biocompatible polymer, is formed by contacting a solidpolyglycol-based, fully synthetic, pre-formulation with a liquidcomponent, comprising at least one solid first compound comprising morethan two nucleophilic groups; and at least one solid second compoundcomprising more than two electrophilic groups. In some embodiments, thesolid polyglycol-based, fully synthetic, pre-formulation furthercomprises a solid buffer component. In some embodiments, thepolyglycol-based, fully synthetic, pre-formulation further comprises atherapeutic agent. In certain embodiments, the liquid componentcomprises water, saline, a buffer, a therapeutic agent or a combinationthereof. In some embodiments, the liquid component comprises water. Inother embodiments, the liquid component comprises saline. In someembodiments, the liquid component comprises a buffer. In certainembodiments, the liquid component comprises a therapeutic agent. In someembodiments, the liquid component comprises of water. In someembodiments, the polyglycol-based, fully synthetic solid pre-formulationfurther comprises a viscosity enhancer. In some embodiments, thepolyglycol-based fully synthetic, pre-formulation further comprises atherapeutic agent.

In another aspect, described herein is a solid pre-formulation,comprising at least one solid first compound comprising more than twonucleophilic groups; and at least one solid second compound comprisingmore than two electrophilic groups; wherein the pre-formulationpolymerizes and/or gels form a biocompatible hydrogel polymer in thepresence of a liquid component. In some embodiments, the solidpre-formulation further comprises a solid buffer component. In certainembodiments, the liquid component comprises water, saline, a buffer, atherapeutic agent or a combination thereof. In some embodiments, theliquid component comprises water. In certain embodiments, the liquidcomponent comprises saline. In some embodiments, the liquid componentcomprises a buffer. In some embodiments, the liquid component comprisesa therapeutic agent. In certain embodiments, the hydrogel polymer atleast partially adheres to a target site. In some embodiments, the solidpre-formulation further comprises a viscosity enhancer. In certainembodiments, the viscosity enhancer is selected fromhydroxyethylcellulose, hydroxypropylmethylcellulose, methylcellulose,polyvinyl alcohol, or polyvinylpyrrolidone

In certain embodiments, the solid pre-formulation further comprises atherapeutic agent. In some embodiments, the therapeutic agent is anantibacterial agent, an antifungal agent, an immunosuppressant agent, ananti-inflammatory agent, a bisphosphonate, gallium nitrate, stem cells,an antiseptic agent, or a lubricity agent. In certain embodiments,anti-inflammatory is s a corticosteroid or a TNF-α inhibitor. In someembodiments, the therapeutic agent is an antiseptic agent.

In some embodiments, the solid pre-formulation is polyglycol-based. Inother embodiments, the solid pre-formulation is fully synthetic. Incertain embodiments, the solid pre-formulation is PEG-based. In someembodiments, the solid pre-formulation is fully synthetic and polyglycolbased. In other embodiments, the solid pre-formulation is fullysynthetic and PEG-based.

In another aspect described herein is a solid biocompatible hydrogelpolymer, comprising at least one solid first monomeric unit boundthrough at least one amide, thioester, or thioether linkage to at leastone solid second monomeric unit; and at least one solid second monomericunit bound to at least one solid first monomeric unit; whereinbiocompatible hydrogel polymer is formed from contacting a solidpre-formulation with a liquid component. In some embodiments, the liquidcomponent comprises water, saline solution, therapeutic agent, or acombination thereof. In certain embodiments, the liquid componentcomprises water. In some embodiments, the liquid component comprises asaline solution. In certain embodiments, the liquid component comprisesa therapeutic agent. In some embodiments, the solid first monomeric unitis a polyol derivative. In certain embodiments, the solid firstmonomeric unit is a glycol, trimethylolpropane, pentaerythritol,hexaglycerol, or tripentaerythritol derivative. In some embodiments, thesolid first monomeric unit further comprises one or more polyethyleneglycol sections. In certain embodiments, the solid first monomeric unitis a pentaerythritol or hexaglycerol derivative. In some embodiments,the solid second monomeric unit is a polyol derivative. In certainembodiments, the solid second monomeric unit is a trimethylolpropane,glycerol, diglycerol, pentaerythritol, sorbitol, hexaglycerol,tripentaerythritol, or polyglycerol derivative. In some embodiments, thesolid second monomeric further comprises one or more polyethylene glycolsections. In certain embodiments, the solid second monomeric unit is atrimethylolpropane, pentaerythritol, or hexaglycerol derivative.

In another aspect described herein is a biocompatible hydrogel polymer,comprising: at least one solid first monomeric unit bound through atleast one amide linkage to at least one solid second monomeric unit; andat least one solid second monomeric unit bound to at least one solidfirst monomeric unit; wherein the biocompatible hydrogel polymer isformed from contacting a solid pre-formulation with a liquid component.In some embodiments, the liquid component comprises water, salinesolution, saline solution, therapeutic agent, or combination thereof. Incertain embodiments, the liquid component comprises water. In someembodiments, the liquid component comprises a saline solution. Incertain embodiments, the liquid component comprises a therapeutic agent.In some embodiments, the solid first monomeric unit is a polyolderivative. In certain embodiments, the solid first monomeric unit is aglycol, trimethylolpropane, pentaerythritol, hexaglycerol, ortripentaerythritol derivative. In some embodiments, the solid firstmonomeric unit further comprises one or more polyethylene glycolsections. In certain embodiments, the solid first monomeric unit is apentaerythritol or hexaglycerol derivative. In some embodiments, thesolid second monomeric unit is a polyol derivative. In certainembodiments, the solid second monomeric unit is a trimethylolpropane,glycerol, diglycerol, pentaerythritol, sorbitol, hexaglycerol,tripentaerythritol, or polyglycerol derivative. In some embodiments, thesolid second monomeric further comprises one or more polyethylene glycolsections. In certain embodiments, the solid second monomeric unit is atrimethylolpropane, pentaerythritol, or hexaglycerol derivative.

BRIEF DESCRIPTION OF THE DRAWINGS

The novel features of the invention are set forth with particularity inthe appended claims. A better understanding of the features andadvantages of the present invention will be obtained by reference to thefollowing detailed description that sets forth illustrative embodiments,in which the principles of the invention are utilized, and theaccompanying drawings of which:

FIG. 1 shows the effect of addition of degradable acetate amine8ARM-20k-AA or 4ARM-20k-AA on degradation times. Degradations occurredin phosphate buffered saline (PBS) at 37° C.

FIG. 2 shows the effect of polymer concentration on degradation time for75% Acetate Amine formulation and 100% Acetate Amine formulation.

FIG. 3 shows the effect of polymer solution on gel time (A), firmness(B), tack (C), and elastic modulus (D) for the formulation:8ARM-20k-AA/8ARM-20k-NH2 (75/25) & 4ARM-20k-SGA with 0.3% HPMC. Theerror bars represent the standard deviations of 3 samples.

FIG. 4 shows the effect of the polymer of Example 13A left in the air asthe percent of water weight loss over time.

FIG. 5 shows a sample plot generated by the Texture Analyzer Exponentsoftware running the firmness test. The peak force was recorded as thepolymer firmness, which represents the point where the targetpenetration depth of 4 mm has been reached by the probe.

FIG. 6 shows a sample plot generated by the Texture Analyzer Exponentsoftware running the elastic modulus test under compression. The moduluswas calculated from the initial slope of the curve up to 10% of themaximum compression stress.

FIG. 7 shows an exemplary plot generated by the Texture AnalyzerExponent software running the adhesion test. A contact force of 100.0 gwas applied for 10 seconds. The tack was measured as the peak forceafter lifting the probe from the sample. The adhesion energy or the workof adhesion was calculated as the area under the curve representing thetack force (points 1 to 2). The stringiness was defined as the distancetraveled by the probe while influencing the tack force (points 1 and 2).

FIG. 8 shows the effect of hypromellose (HPMC) addition at 0, 0.3 and1.0% to the polymer formulations on firmness (A). Effect of degradableacetate amine 8ARM-20k-AA addition at 0, 70 and 100% to the polymerformulations on firmness (B).

FIG. 9 shows the effect of hypromellose (HPMC) addition at 0, 0.3 and1.0% to the polymer formulations on the elastic modulus (A) and showsthe effect Effect of degradable acetate amine 8ARM-20k-AA addition at 0,70 and 100% to the polymer formulations on the elastic modulus (B).

FIG. 10 shows a comparison of the firmness (A), tack (B), adhesionenergy (C) and stringiness (D) of the general polymer formulation:8ARM-20k-AA/8ARM-20k-NH2 (x/y) & 4ARM-20k-SGA at 4.8% solution with 0.3%HPMC. The measured values for a Post-It™ note are included as areference.

FIG. 11 shows the firmness vs. degradation time plotted as percentagesfor the polymer formulation: 8ARM-20k-AA/8ARM-20k-NH2 (70/30) &4ARM-20k-SGA at 4.8% solution with 0.3% HPMC. The error bars representthe standard deviations of 3 samples. The degradation time for thepolymer was 18 days.

FIG. 12 shows the effect of additives on the polymer gel time (A),degradation time (B), firmness (C), adhesion (D) and elastic modulus(E).

FIG. 13 shows the effect of using Kenalog-10 or Depo-Medrol with thesingle syringe system on the polymer firmness (A), adhesion (B) andelastic modulus (C).

FIG. 14 shows the optical clarity of 3 mm thick polymer slices, asmeasured by the % transmission at 400, 525 and 650 nm.

FIG. 15 shows for the polymer of Example 13A, the cumulative % elutionof chlorhexidine.

FIG. 16 shows that for the polymer of Example 13B, the triamcinolonecumulative % elution for 60, 90 and 240 day polymers.

FIG. 17 shows that for short degradation time version of the polymer ofExample 13B loaded with Depo-Medrol, the methylprednisolone cumulative %elution.

FIG. 18 shows that for long degradation time version of the polymer ofExample 13B loaded with Depo-Medrol, the methylprednisolone cumulative %elution.

FIG. 19 shows the effect of solid phosphate powder concentration onpolymer gel time (A) and solution pH (B).

FIG. 20 shows the effect of sterilization on gel times for polymers ofvarious concentrations (A) and (B). For example, a sterile 6 to 7%polymer behaves similarly to a non-sterile 4 to 5% polymer.

FIG. 21 shows the storage stability of kits at 5° C., 20° C. and 37° C.

DETAILED DESCRIPTION OF THE INVENTION

To help close the wounds and control infection, a cyanoacrylate basedglue material is used. Even though the glue works effectively to sealthe wounds, it is highly toxic and thus results in complications.Furthermore, doctors need an easily prepared and versatile formulationthat can be easily adapted to different uses (external or internal)across a wide range of medical conditions, as well as optionally containadditional components like therapeutic agents or compounds that modifythe physiochemical properties of the formulation.

Provided herein are solid non-toxic pre-formulations that form abiocompatible hydrogel polymer that is easily applied. The solidpre-formulation may be used to prepare and deliver a biocompatiblehydrogel polymer to a target site. For instance, the target site may bea wound or a joint space. Once applied, e.g., sprayed over the wound, inthe liquid form after addition of a liquid component to the solidpre-formulation, the liquid formulation gels quickly and forms a solidhydrogel polymer layer, for instance, over the wound or filling thejoint space. The biocompatible hydrogel polymer seals the wound and italso sticks to the surrounding skin to form a suture. The biocompatiblehydrogel polymer layer over the wound acts as a barrier to keep thewound from getting infected. In some instances, the biocompatiblehydrogel polymer layer in contact with the skin makes the skin surfacesticky and thus allows the bandage to stick to the skin moreeffectively. Most importantly, the biocompatible hydrogel polymer isnon-toxic. After the wound healing has taken place, the biocompatiblehydrogel polymer dissolves and is absorbed without producing toxicby-products. In certain embodiments, the wound is on a mammal. In someembodiments, the mammal is a human. In order embodiments, the mammal isan animal. In some embodiments, the animal is a dog, a cat, a cow, apig, or a horse.

The solid pre-formulations presented herein are convenient, versatile,and adaptable, wherein the pre-formulation comprises a solid firstcompound and a solid second compound that only gel/polymerize to formthe biocompatible hydrogel polymer after addition of a liquid component.Additionally, a buffer component, therapeutic agents, and viscosityenhancers may be added in solid form to the solid pre-formulation or maybe present in the liquid component.

In some embodiments, the biocompatible hydrogel polymer is also loadedwith one or more therapeutic agents, such as antibiotics. The physicaland chemical nature of the biocompatible hydrogel polymer is such that alarge variety of commonly available therapeutic agents can be with thepre-formulation that forms the biocompatible hydrogel polymer. Incertain embodiments, the pre-formulation is applied to a wound withoutthe therapeutic agent losing activity. In some embodiments, thetherapeutic agent is an anti-infective agent, such as an aminoglycosideantibiotic, a fluoroquinolone, a macrolide antibiotic, an antifungalagent, or an antibacterial agent. In certain embodiments, the antibioticis neomycin, bacitracin zinc or polymyxin B sulfates etc. In someembodiments, the therapeutic agent is an antibacterial agent. In certainembodiments, the therapeutic agent is an antiseptic agent, such aschlorhexidine. In other embodiments, the therapeutic agent is alubricity agent. In specific embodiments, the lubricity agent ishyaluronic acid.

The amount of materials used for covering a wound depends on the size ofthe wound. Most common wounds may be about 1 cm² and up to as much as 30cm². In certain embodiments, the biocompatible hydrogel polymer keepsthe wound sealed for 24-48 hours and protects it from infection, whichavoids repeat visits to the hospital and thus saving costs.

Furthermore, mammals commonly suffer from arthritis in small “lowmotion” joints. In both animals and humans, these arthritic joints maycause a significant amount of pain. In some instances, the arthritiscauses lameness and owner distress. Provided herein, arepre-formulations that are delivered into the joint to form abiocompatible hydrogel polymer. In certain embodiments, thebiocompatible hydrogel polymer acts as a “joint spacer” to decrease theamount of bone to bone pressure in these “low motion” joints. In someembodiments, the biocompatible hydrogel polymer is substantiallynon-absorbable. In certain embodiments, the amount of pre-formulationdelivered into the joint space is about 4 mL. In some embodiments, thepre-formulation also comprises a therapeutic agent. In certainembodiments, the therapeutic agent is an antibiotic to prevent jointinfection. In other embodiments, the therapeutic agent is ananti-inflammatory drug, such as an NSAID or a TNF-alpha inhibitor. Insome embodiments, the therapeutic agent comprises bisphosphonates,corticosteroids, gallium nitrate or stem cells. In certain embodiments,the therapeutic agent is a corticosteroid. In some embodiments, thecorticosteroid is trimacinolone or methylprednisolone. In otherembodiments, the therapeutic agent comprises a lubricity agent. Inspecific embodiments, the lubricity agent is hyaluronic acid.

In addition, in horses Navicular disease is degeneration of the distalsesamoid bone, which causes millions of dollars lost in the equinecommunity. Provided herein is a pre-formulation that forms abiocompatible hydrogel polymer that acts as a gel cushion between thedeep digital flexor tendon and the navicular bone. In some embodiments,the biocompatible hydrogel polymer is substantially non-absorbable. Incertain embodiments, the biocompatible hydrogel polymer bioabsorbs overtime. In certain embodiments, the amount of pre-formulation deliveredinto the joint space is about 2-3 mL. In some embodiments, thepre-formulation also comprises a therapeutic agent. In certainembodiments, the therapeutic agent is an antibiotic to prevent jointinfection. In other embodiments, the therapeutic agent is ananti-inflammatory drug, such as an NSAID or a TNF-alpha inhibitor. Insome embodiments, the therapeutic agent comprises bisphosphonates,corticosteroids, gallium nitrate or stem cells. In certain embodiments,the therapeutic agent is a corticosteroid. In some embodiments, thecorticosteroid is trimacinolone or methylprednisolone. In otherembodiments, the therapeutic agent comprises a lubricity agent. Inspecific embodiments, the lubricity agent is hyaluronic acid.

In some instances, the therapeutic agent is released from thebiocompatible hydrogel polymer over an extended period of time. Incertain instances, delivery of the therapeutic agent in a biocompatiblehydrogel polymer provides a depot of the therapeutic agent (e.g., underthe skin), wherein the depot releases the therapeutic agent over anextended period of time (e.g., 1 day, 2 days, 3 days, 4 days, 5 days, 6days, 7 days, 10, days, 14 days, 3 week, 4 week). In some instances, thebiocompatible hydrogel polymer releases the therapeutic agent after adelay as a delayed burst.

Solid Pre-Formulations

The solid pre-formulation comprises at least one solid first compoundcomprising more than two nucleophilic groups and at least one solidsecond compound comprising more than two electrophilic groups. In someembodiments, the pre-formulation comprises two solid first compoundscomprising more than two nucleophilic grous. In certain embodiments, thepre-formulation comprises two solid second compounds comprising morethan two electrophilic groups. In some embodiments the pre-formulationcomprises two solid first compounds comprising more than twonucleophilic groups and one solid second compound comprising more thantwo electrophilic groups. In certain embodiments the pre-formulationcomprises one solid first compounds comprising more than twonucleophilic groups and two solid second compounds comprising more thantwo electrophilic groups.

In further embodiments, the solid pre-formulation comprises one or moreadditional components. In some embodiments, the solid pre-formulationcomprises a buffer component, one or more therapeutic agents, viscosityenhancers, lubricity agents, or any combination thereof, wherein each ofthese identified components are added to the pre-formulation in itsrespective solid form. In some embodiments, the solid pre-formulationcomprises a lubricity agent in its solid form. In certain embodiments,the solid pre-formulation comprises solid hyaluronic acid.

Liquid Component

The liquid component is added to the pre-formulation to form a liquidformulation, wherein the liquid formulation gels/polymerizes to form ahydrogel. In some embodiments, the liquid component is aqueous buffer.In some embodiments, the liquid component comprises buffer, one or moretherapeutic agents, viscosity enhancer, water, saline, lubricity agents,or any combination thereof, wherein each of the variables identified arein its respective liquid or solution state. In some embodiments, theliquid component may also comprise a further first or second compoundthat is delivered in liquid or solution form.

In some embodiments, the additional components (e.g., the viscosityenhancer) improve the dissolution of the first and second compound uponaddition of the liquid component. Furthermore, the viscosity of theliquid formulation formed after addition to the liquid component to thepre-formulation may be influenced by the viscosity enhancer.

Hydrogel

Once the liquid component is added to the solid pre-formulation, aliquid formulation is formed that can be delivered to a target site toform a biocompatible hydrogel polymer. The gelling time of the liquidformulation to form the biocompatible hydrogel polymer may be controlledthrough the selection of suitable first and second compounds and theconcentration of the pre-formulation in the liquid component. In someembodiments, the gelling time is influenced by the pH of the liquidcomponent. In some embodiments, the gelling time is influenced by the pHprovided by the solid buffer component upon the addition of the liquidcomponent. The bioabsorption of the hydrogel polymer is also controlledthrough the selection of first and second compounds. In someembodiments, the degradation of the hydrogel is controlled by theconcentration of ester groups in the first or second compound. In someembodiments, the stickiness of the hydrogel polymer is influenced by themolar ratio of the first and second compound. In other embodiments, thestickiness of the hydrogel polymer is controlled by the percent ofdegradable acetate amine by mole equivalents. In some embodiments, thestickiness of the hydrogel polymer is controlled by the percent ofdegradable amine between the first compound and a different firstcompound.

Exemplary Solid Pre-formulations

Provided herein are several types of exemplary pre-formulations, whereinthe pre-formulations are in solid form. As several types ofpre-formulations are presented herein, all descriptions pertainingpre-formulations are meant to encompass all the bicompatiblepre-formulation presented herein. Furthermore, as the biocompatiblehydrogel polymers are formed from the pre-formulations described herein,the descriptions pertaining to biocompatible hydrogel polymers are alsomeant to encompass all the biocompatible hydrogel polymers presentedherein.

In some embodiments, the pre-formulation is polyglycol-based. In someembodiments, polyglycol-based pre-formulations include polyethyleneglycol, polypropylene glycol, polybutylene glycol, polyalkyl glycols ofvarious chain lengths, and any combination or copolymers thereof. Insome embodiments, the polyglycol-based pre-formulation comprisespolyethylene glycols (PEGs), methoxypolyethylene glycols (MPEGs),polypropylene glycols (PPGs), polybutylene glycols (PBGs), andpolyglycol copolymers. In some embodiments, the biocompatiblepre-formulation is PEG-based. In some embodiments, the pre-formulationis fully synthetic. In some embodiments, the pre-formulation is fullysynthetic and PEG-based. In certain embodiments, the pre-formulation isfully synthetic and polyglycol based.

Presented herein is a solid polyglycol-based, fully synthetic,pre-formulation, comprising at least one first compound comprising morethan two nucleophilic groups; and at least one second compoundcomprising more than two electrophilic groups; wherein the solidpolyglycol based, fully synthetic, pre-formulation polymerizes and/orgels to form a polyglycol-based, fully synthetic, biocompatible hydrogelpolymer in the presence of a liquid component. In some embodiments, thesolid polyglycol-based, fully synthetic, pre-formulation is made bymixing the first compound and second compound to form a component. Insome embodiments, the first compound further comprises a second firstcompound. In certain embodiments, the solid polyglycol-based, fullysynthetic, pre-formulation, further comprises a solid buffer. In someembodiments, the solid polyglycol-based, fully synthetic, biocompatiblehydrogel polymer at least partially adheres to a target site. In someembodiments, the solid polyglycol-based, fully synthetic,pre-formulation, further comprises a therapeutic agent. In someembodiments, the solid polyglycol-based, fully synthetic,pre-formulation, further comprises a viscosity enhancer. In someembodiments, the solid polyglycol-based, fully synthetic,pre-formulation, further comprises a radiopaque material or apharmaceutically acceptable dye.

Also presented herein is a solid pre-formulation, comprising at leastone first compound comprising more than two nucleophilic groups; and atleast one second compound comprising more than two electrophilic groups;wherein the pre-formulation polymerizes and/or gels form a biocompatiblehydrogel polymer in the presence of a liquid component. In someembodiments, the solid pre-formulation is made by mixing the firstcompound and second compound to form a solid component. In someembodiments, the first compound further comprises a second firstcompound. In some embodiments, the solid pre-formulation, furthercomprises a buffer. In some embodiments, the solid biocompatiblehydrogel polymer at least partially adheres to a target site. In someembodiments, the solid pre-formulation, further comprises a therapeuticagent. In some embodiments, the solid pre-formulation, further comprisesa viscosity enhancer. In some embodiments, the solid pre-formulation,further comprises a radiopaque material or a pharmaceutically acceptabledye.

Further presented herein is the pre-formulation comprising at least onefirst compound comprising more than one nucleophilic group, at least onesecond compound comprising more than one electrophilic group, and abuffer component providing pH range of about 5.0 to about 9.5, andoptionally one or more therapeutic agents. In some embodiments thebuffer is a solid buffer, wherein upon the addition of a liquidcomponent as described to provide an aqueous buffer. In someembodiments, the buffer is an aqueous buffer. In certain embodiments,the pre-formulation forms a biocompatible hydrogel polymer at a targetsite in a human body by mixing the at least one first compound, the atleast one second compound, and the optional therapeutic agent in theaqueous buffer and delivering the mixture to the target site such thatthe biocompatible hydrogel polymer at least in part polymerizes and/orgels at the target site. In some embodiments, the biocompatible hydrogelpolymer is formed following mixing the first compound and the secondcompound in the aqueous buffer; and wherein the biocompatible hydrogelpolymer gels at a target site. In certain embodiments, mixing the firstcompound, the second compound, and the optional therapeutic agent in theaqueous buffer and delivering the mixture to a target site in the humanbody generates the pre-formulation such that the pre-formulation atleast in part polymerizes and/or gels at the target site to form abiocompatible hydrogel polymer. In some embodiments, the first compoundfurther comprises a second first compound. In some embodiments, thefirst compound and second compound are combined to form a solidcomponent where the biocompatible hydrogel polymer is formed upon theaddition of the liquid component. In some embodiments, the solidcomponent further comprises buffer. In certain embodiments, the solidcomponent further comprises therapeutic agent. In some embodiments, thepre-formulation, further comprises a viscosity enhancer. In someembodiments, the pre-formulation, further comprises a radiopaquematerial or a pharmaceutically acceptable dye.

For certain embodiments of the solid pre-formulation, a liquidbiocompatible formulation is formed from the addition of a liquidcomponent to the solid pre-formulation. The liquid biocompatibleformulation gels to form the biocompatible hydrogel polymer. In someembodiments, the liquid component comprises water, saline, a buffer, atherapeutic agent or a combination thereof. In certain embodiments, theliquid component comprises water. In certain embodiments, the liquidcomponent comprises saline. In certain embodiments, the liquid componentcomprises a buffer. In certain embodiments, the liquid componentcomprises a therapeutic agent.

In some embodiments, the first or second compound comprises more thanone nucleophilic or electrophilic group. In certain embodiments, thefirst or second compound comprises more than two nucleophilic orelectrophilic groups. In some embodiments, the first or second compoundis a polyol derivative. In certain embodiments, the first or secondcompound is a dendritic polyol derivative. In some embodiments, thefirst or second compound is a glycol, trimethylolpropane, glycerol,diglycerol, pentaerythritiol, sorbitol, hexaglycerol,tripentaerythritol, or polyglycerol derivative. In some embodiments, thefirst or second compound is a trimethylolpropane, glycerol, diglycerol,pentaerythritiol, sorbitol, hexaglycerol, tripentaerythritol, orpolyglycerol derivative. In certain embodiments, the first or secondcompound is a glycol, trimethylolpropane, pentaerythritol, hexaglycerol,or tripentaerythritol derivative. In certain embodiments, the first orsecond compound is a trimethylolpropane, pentaerythritol, hexaglycerol,or tripentaerythritol derivative. In some embodiments, the first orsecond compound is a trimethylolpropane, glycerol, diglycerol,pentaerythritiol, sorbitol, hexaglycerol, tripentaerythritol, orpolyglycerol derivative. In some embodiments, the first or secondcompound is a pentaerythritol, di-pentaerythritol, or tripentaerythritolderivative. In certain embodiments, the first or second compound is ahexaglycerol (2-ethyl-2-(hydroxymethyl)-1,3-propanediol,trimethylolpropane) derivative. In some embodiments, the first or secondcompound is a sorbitol derivative. In certain embodiments, the first orsecond compound is a glycol, propyleneglycol, glycerin, diglycerin, orpolyglycerin derivative.

In some embodiments, the first and/or second compound further comprisespolyethylene glycol (PEG) chains comprising one to 200 ethylene glycolsubunits. In certain embodiments, the first and/or second compoundfurther comprises polypropylene glycol (PPG) chains comprising one to200 propylene glycol subunits. The PEG or PPG chains extending from thepolyols are the “arms” linking the polyol core to the nucleophilic orelectrophilic groups.

Exemplary Nucleophilic Monomers

The pre-formulation comprises at least one first compound comprisingmore than one nucleophilic group. In some embodiments, thepre-formulation comprises at least one first compound comprising morethan two nucleophilic groups. In some embodiments, the nucleophilicgroup comprises a hydroxyl, thiol, or amino group. In preferredembodiments, the nucleophilic group comprises a thiol or amino group. Incertain embodiments, the nucleophilic group comprises an amino group.

In certain embodiments, the nucleophilic group is connected to thepolyol derivative through a suitable linker. Suitable linkers include,but are not limited to, esters (e.g., acetates) or ethers. In someinstances, monomers comprising ester linkers are more susceptible tobiodegradation. Examples of linkers comprising a nucleophilic groupinclude, but are not limited to, mercaptoacetate, aminoacetate (glycin)and other amino acid esters (e.g., alanine, β-alanine, lysine,ornithine), 3-mercaptopropionate, ethylamine ether, or propylamineether. In some embodiments, the polyol core derivative is bound to apolyethylene glycol or polypropylene glycol subunit, which is connectedto the linker comprising the nucleophilic group. The molecular weight ofthe first compound (the nucleophilic monomer) is about 500 to 40000. Incertain embodiments, the molecular weight of a first compound (anucleophilic monomer) is about 100, about 500, about 1000, about 2000,about 3000, about 4000, about 5000, about 6000, about 7000, about 8000,about 9000, about 10000, about 12000, about 15000, about 20000, about25000, about 30000, about 35000, about 40000, about 50000, about 60000,about 70000, about 80000, about 90000, or about 100000. In someembodiments, the molecular weight of a first compound is about 500 to2000. In certain embodiments, the molecular weight of a first compoundis about 15000 to about 40000. In some embodiments, the first compoundis water soluble.

In some embodiments, the first compound is a MULTIARM-(5k-50k)-polyolderivative comprising polyglycol subunits and more than two nucleophilicgroups. MULTIARM refers to number of polyglycol subunits that areattached to the polyol core and these polyglycol subunits link thenucleophilic groups to the polyol core. In some embodiments, MULTIARM is3ARM, 4ARM, 6ARM, 8ARM, 10ARM, or 12ARM. In some embodiments, MULTIARMis 3ARM, 4ARM, 6ARM, or 8ARM. In some embodiments, the MULTIARM is 4ARMor 8ARM. In some embodiments, the first compound isMULTIARM-(5k-50k)-SH, MULTIARM-(5k-50k)-NH2, MULTIARM-(5k-50k)-AA, or acombination thereof. In certain embodiments, the first compound is4ARM-(5k-50k)-SH, 4ARM-(5k-50k)-NH2, 4ARM-(5k-50k)-AA,8ARM-(5k-50k)-NH2, 8ARM-(5k-50k)-AA or a combination thereof. In someembodiments, the polyol derivative is a trimethylolpropane, diglycerol,pentaerythritol, sorbitol, hexaglycerol, tripentaerythritol, orpolyglycerol derivative.

Examples of the construction of monomers comprising more than onenucleophilic group are shown below with a trimethylolpropane orpentaerythritol core polyol. The compounds shown have thiol or amineelectrophilic groups that are connected to variable lengths PEG subunitthrough acetate, propionate or ethyl ether linkers (e.g., structuresbelow of ETTMP (A; n=1), 4ARM-PEG-NH2 (B; n=1), and 4ARM-PEG-AA (C;n=1)). Monomers using other polyol cores are constructed in a similarway.

Suitable first compounds comprising a nucleophilic group (used in theamine-ester chemistry) include, but are not limited to, pentaerythritolpolyethylene glycol amine (4ARM-PEG-NH2) (molecular weight selected fromabout 5000 to about 40000, e.g., 5000, 10000, or 20000), pentaerythritolpolyethylene glycol amino acetate (4ARM-PEG-AA) (molecular weightselected from about 5000 to about 40000, e.g., 5000, 10000, or 20000),hexaglycerin polyethylene glycol amine (8ARM-PEG-NH2) (molecular weightselected from about 5000 to about 40000, e.g., 10000, 20000, or 40000),or tripentaerythritol glycol amine (8ARM (TP)-PEG-NH2) (molecular weightselected from about 5000 to about 40000, e.g., 10000, 20000, or 40000).Within this class of compounds, 4(or 8)ARM-PEG-AA comprises ester (oracetate) groups while the 4(or 8)ARM-PEG-NH2 monomers do not compriseester (or acetate) groups. In some embodiments, the first compound is4ARM-5k-SH, 4ARM-2k-NH2, 4ARM-5k-NH2, 8ARM-20k-NH2, 4ARM-20k-AA, or8ARM-20k-AA. In some embodiments, the first compound is 4ARM-5k-SH,4ARM-2k-NH2, 4ARM-5k-NH2, 8ARM-20k-NH2, 4ARM-20k-AA, 8ARM-20k-AA, or acombination thereof. In certain embodiments, the first compound furthercomprising a second first compound is 4ARM-5k-SH, 4ARM-2k-NH2,4ARM-5k-NH2, 8ARM-20k-NH2, 4ARM-20k-AA, or 8ARM-20k-AA.

Other suitable first compounds comprising a nucleophilic group (used inthe thiol-ester chemistry) include, but not limited to, glycoldimercaptoacetate (THIOCURE® GDMA), trimethylolpropanetrimercaptoacetate (THIOCURE® TMPMA), pentaerythritoltetramercaptoacetate (THIOCURE® PETMA), glycol di-3-mercaptopropionate(THIOCURE® GDMP), trimethylolpropane tri-3-mercaptopropionate (THIOCURE®TMPMP), pentaerythritol tetra-3-mercaptopropionate (THIOCURE® PETMP),polyol-3-mercaptopropionates, polyester-3-mercaptopropionates,propyleneglycol 3-mercaptopropionate (THIOCURE® PPGMP 800),propyleneglycol 3-mercaptopropionate (THIOCURE® PPGMP 2200), ethoxylatedtrimethylolpropane tri-3-mercaptopropionate (THIOCURE® ETTMP-700), andethoxylated trimethylolpropane tri-3-mercaptopropionate (THIOCURE®ETTMP-1300).

Exemplary Electrophilic Monomers

The pre-formulation comprises at least one second compound comprisingmore than one electrophilic group. In some embodiments, thepre-formulation comprises at least one second compound comprising morethan two electrophilic groups. In some embodiments, the electrophilicgroup is an epoxide, maleimide, succinimidyl, or an alpha-betaunsaturated ester. In preferred embodiments, the electrophilic group isan epoxide or succinimidyl. In some embodiments, the electrophilic groupis N-succinimidyl glutaramide.

In certain embodiments, the electrophilic group is connected to thepolyol derivative through a suitable linker. Suitable linkers include,but are not limited to, esters, amides, or ethers. In some instances,monomers comprising ester linkers are more susceptible tobiodegradation. Examples of linkers comprising an electrophilic groupinclude, but are not limited to, succinimidyl succinate, succinimidylglutarate, succinimidyl succinamide, succinimidyl glutaramide, orglycidyl ether. In some embodiments, the polyol core derivative is boundto a polyethylene glycol or polypropylene glycol subunit, which isconnected to the linker comprising the electrophilic group. Themolecular weight of the second compound (the electophilic monomer) isabout 500 to 40000. In certain embodiments, the molecular weight of asecond compound (an electophilic monomer) is about 100, about 500, about1000, about 2000, about 3000, about 4000, about 5000, about 6000, about7000, about 8000, about 9000, about 10000, about 12000, about 15000,about 20000, about 25000, about 30000, about 35000, about 40000, about50000, about 60000, about 70000, about 80000, about 90000, or about100000. In some embodiments, the molecular weight of a second compoundis about 500 to 2000. In certain embodiments, the molecular weight of asecond compound is about 15000 to about 40000. In some embodiments, thesecond compound is water soluble.

In some embodiments, the second compound is a MULTIARM-(5k-50k)-polyolderivative comprising polyglycol subunits and more than twoelectrophilic groups. MULTIARM refers to number of polyglycol subunitsthat are attached to the polyol core and these polyglycol subunits linkthe nucleophilic groups to the polyol core. In some embodiments,MULTIARM is 3ARM, 4ARM, 6ARM, 8ARM, 10ARM, or 12ARM. In someembodiments, MULTIARM is 3ARM, 4ARM, 6ARM, or 8ARM. In some embodiments,MULTIARM is 4ARM or 8ARM. In certain embodiments, the second compoundMULTIARM-(5-50k)-SG, MULTIARM-(5-50k)-SGA, MULTIARM-(5-50k)-SS,MULTIARM-(5-50k)-SSA, or a combination thereof. In certain embodiments,the second compound is 4ARM-(5-50k)-SG, 4ARM-(5-50k)-SGA,4ARM-(5-50k)-SS, 8ARM-(5-50k)-SG, 8ARM-(5-50k)-SGA, 8ARM-(5-50k)-SS, ora combination thereof. In some embodiments, the polyol derivative is atrimethylolpropane, diglycerol, pentaerythritol, sorbitol, hexaglycerol,tripentaerythritol, or polyglycerol derivative.

Examples of the construction of monomers comprising more than oneelectrophilic group are shown below with a pentaerythritol core polyol.The compounds shown have a succinimidyl electrophilic group, a glutarateor glutaramide linker, and a variable lengths PEG subunit (e.g.,structures below of 4ARM-PEG-SG (D; n=3) and 4ARM-PEG-SGA (E; n=3)).Monomers using other polyol cores or different linkers (e.g., succinate(SS) or succinamide (SSA) are constructed in a similar way.

Suitable second compounds comprising an electrophilic group include, butare not limited to, pentaerythritol polyethylene glycol maleimide(4ARM-PEG-MAL) (molecular weight selected from about 5000 to about40000, e.g., 10000 or 20000), pentaerythritol polyethylene glycolsuccinimidyl succinate (4ARM-PEG-SS) (molecular weight selected fromabout 5000 to about 40000, e.g., 10000 or 20000), pentaerythritolpolyethylene glycol succinimidyl glutarate (4ARM-PEG-SG) (molecularweight selected from about 5000 to about 40000, e.g., 10000 or 20000),pentaerythritol polyethylene glycol succinimidyl glutaramide(4ARM-PEG-SGA) (molecular weight selected from about 5000 to about40000, e.g., 10000 or 20000), hexaglycerin polyethylene glycolsuccinimidyl succinate (8ARM-PEG-SS) (molecular weight selected fromabout 5000 to about 40000, e.g., 10000 or 20000), hexaglycerinpolyethylene glycol succinimidyl glutarate (8ARM-PEG-SG) (molecularweight selected from about 5000 to about 40000, e.g., 10000, 15000,20000, or 40000), hexaglycerin polyethylene glycol succinimidylglutaramide (8ARM-PEG-SGA) (molecular weight selected from about 5000 toabout 40000, e.g., 10000, 15000, 20000, or 40000), tripentaerythritolpolyethylene glycol succinimidyl succinate (8ARM(TP)-PEG-SS) (molecularweight selected from about 5000 to about 40000, e.g., 10000 or 20000),tripentaerythritol polyethylene glycol succinimidyl glutarate(8ARM(TP)-PEG-SG) (molecular weight selected from about 5000 to about40000, e.g., 10000, 15000, 20000, or 40000), or tripentaerythritolpolyethylene glycol succinimidyl glutaramide (8ARM(TP)-PEG-SGA)(molecular weight selected from about 5000 to about 40000, e.g., 10000,15000, 20000, or 40000). The 4(or 8)ARM-PEG-SG monomers comprise estergroups, while the 4(or 8)ARM-PEG-SGA monomers do not comprise estergroups. In some embodiments, the second compound is 4ARM-10k-SG,8ARM-15k-SG, 4ARM-20k-SGA, and 4ARM-10k-SS. In some embodiments, thesecond compound is 4ARM-10k-SG, 8ARM-15k-SG, 4ARM-20k-SGA, 4ARM-10k-SS,or a combination thereof. In certain embodiments, the first compound is8ARM-20k-NH2 and/or 8ARM-20k-AA, and the second compound is4ARM-20k-SGA.

Other suitable second compounds comprising an electrophilic group aresorbitol polyglycidyl ethers, including, but not limited to, sorbitolpolyglycidyl ether (DENACOL® EX-611), sorbitol polyglycidyl ether(DENACOL® EX-612), sorbitol polyglycidyl ether (DENACOL® EX-614),sorbitol polyglycidyl ether (DENACOL® EX-614 B), polyglycerolpolyglycidyl ether (DENACOL® EX-512), polyglycerol polyglycidyl ether(DENACOL® EX-521), diglycerol polyglycidyl ether (DENACOL® EX-421),glycerol polyglycidyl ether (DENACOL® EX-313), glycerol polyglycidylether (DENACOL® EX-313), trimethylolpropane polyglycidyl ether (DENACOL®EX-321), sorbitol polyglycidyl ether (DENACOL® EJ-190).

Formation of Hydrogels

In certain embodiments, the first and second compounds comprising morethan one nucleophilic or more than one electrophilic group safelyundergo polymerization at a target site inside or on a mammalian body,for instance at the site of a wound or in a joint. In certainembodiments, the first and second compounds comprising more than twonucleophilic or more than two electrophilic groups safely undergopolymerization at a target site inside or on a mammalian body, forinstance at the site of a wound or in a joint. In certain embodiments,the pre-formulation forms a wound patch, suture, or joint spacer afteraddition of a liquid component. In some embodiments, the first compoundand the second compound are monomers forming a polymer through thereaction of a nucleophilic group in the first compound with theelectrophilic group in the second compound. In certain embodiments, themonomers are polymerized at a predetermined time. In some embodiments,the monomers are polymerized under mild and nearly neutral pHconditions. In certain embodiments, the hydrogel polymer does not changevolume after curing.

In some embodiments, the first and second compounds react to form amide,thioester, or thioether bonds. When a thiol nucleophile reacts with asuccinimidyl electrophile, a thioester is formed. When an aminonucleophile reacts with a succinimidyl electrophile, an amide is formed.

In some embodiments, one or more first compounds comprising an aminogroup react with one or more second compounds comprising a succinimidylester group to form amide linked first and second monomer units. Incertain embodiments, one or more first compounds comprising a thiolgroup react with one or more second compounds comprising a succinimidylester group to form thioester linked first and second monomer units. Insome embodiments, one or more first compounds comprising an amino groupreact with one or more second compounds comprising an epoxide group tofrom amine linked first and second monomer units. In certainembodiments, one or more first compounds comprising a thiol group reactwith one or more second compounds comprising an epoxide group to formthioether linked first and second monomer units.

In some embodiments, the biocompatible hydrogel polymer comprises atleast one first monomeric unit bound through at least one amide,thioester, or thioether linkage to at least one second monomeric unit;and at least one second monomeric unit bound to at least one firstmonomeric unit; wherein the biocompatible hydrogel polymer is formedfrom contacting a solid pre-formulation with a liquid component. In someembodiments, the biocompatible hydrogel polymer, comprises at least onefirst monomeric unit bound through at least one amide linkage to atleast one second monomeric unit; and at least one second monomeric unitbound to at least one first monomeric unit; wherein biocompatiblehydrogel polymer is formed from contacting a solid pre-formulation witha liquid component. In certain embodiments, the first monomeric unit isa glycol, trimethylolpropane, pentaerythritol, hexaglycerol, ortripentaerythritol derivative. In some embodiments, the first monomericunit further comprises one or more polyethylene glycol sections. Incertain embodiments, the first monomeric unit is a pentaerythritol orhexaglycerol derivative. In some embodiments, the second monomeric unitis a polyol derivative. In certain embodiments, the second monomericunit is a trimethylolpropane, glycerol, diglycerol, pentaerythritol,sorbitol, hexaglycerol, tripentaerythritol, or polyglycerol derivative.In some embodiments, the second monomeric further comprises one or morepolyethylene glycol sections. In certain embodiments, the secondmonomeric unit is a trimethylolpropane, pentaerythritol, or hexaglycerolderivative.

In some embodiments, a solid first compound is mixed with a differentsolid first compound, or solid second first compound, before addition toone or more solid second compounds. In other embodiments, a solid secondcompound is mixed with a different solid second compound before additionto one or more solid first compounds. In certain embodiments, theproperties of the pre-formulation and the biocompatible hydrogel polymerare controlled by the properties of the at least one first and at leastone second monomer mixture.

In some embodiments, one first compound is used in the biocompatiblehydrogel polymer. In certain embodiments, two different first compoundsare mixed and used in the biocompatible hydrogel polymer. In someembodiments, three different first compounds are mixed and used in thebiocompatible hydrogel polymer. In certain embodiments, four or moredifferent first compounds are mixed and used in the biocompatiblehydrogel polymer.

In some embodiments, one second compound is used in the biocompatiblehydrogel polymer. In certain embodiments, two different second compoundsare mixed and used in the biocompatible hydrogel polymer. In someembodiments, three different second compounds are mixed and used in thebiocompatible hydrogel polymer. In certain embodiments, four or moredifferent second compounds are mixed and used in the biocompatiblehydrogel polymer.

In some embodiments, a first compound comprising ether linkages to thenucleophilic group are mixed with a different first compound comprisingester linkages to the nucleophilic group. This allows the control of theconcentration of ester groups in the resulting biocompatible hydrogelpolymer. In certain embodiments, a second compound comprising esterlinkages to the electrophilic group are mixed with a different secondcompound comprising ether linkages to the electrophilic group. In someembodiments, a second compound comprising ester linkages to theelectrophilic group are mixed with a different second compoundcomprising amide linkages to the electrophilic group. In certainembodiments, a second compound comprising amide linkages to theelectrophilic group are mixed with a different second compoundcomprising ether linkages to the electrophilic group.

In some embodiments, a first compound comprising an aminoacetatenucleophile is mixed with a different first compound comprising anethylamine ether nucleophile at a specified molar ratio (x/y). Incertain embodiments, the molar ratio (x/y) is 5/95, 10/90, 15/85, 20/80,25/75, 30/70, 35/65, 40/60, 45/55, 50/50, 55/45, 60/40, 65/35, 70/30,75/25, 80/20, 85/15, 90/10, or 95/5. In certain embodiments, the mixtureof two first compounds is mixed with one or more second compounds at amolar amount equivalent to the sum of x and y.

In some embodiments, the solid pre-formulation comprising first compoundcomprising more than one nucleophilic group and the second compoundcomprising more than one electrophilic group is mixed together with aliquid component comprising an aqueous buffer in the pH range of about5.0 to about 9.5, whereby a biocompatible hydrogel polymer is formed.

In some embodiments, the solid pre-formulation comprising first orsecond compound comprises more than two nucleophilic or electrophilicgroups. In some embodiments, the first and second compounds are combinedfirst to form a solid component and the compounds are mixed togetherupon the addition of a liquid component comprising an aqueous bufferwhich may optionally further comprise a therapeutic agent.

In some embodiments, the buffer component is provided in solid form andan aqueous buffer is provided upon the addition of a liquid component.In some embodiments, the liquid component can be water or saline. Incertain embodiments, the liquid component further comprises atherapeutic agent. In certain embodiments, the solid first compound, thesolid second compound and solid buffer are combined first to form asolid component, wherein the compounds are mixed together upon theaddition of a liquid component. In other embodiments, the solid firstcompound, the solid second compound, and at least one solid therapeuticagent are combined first to make a solid component, wherein thecompounds are mixed together upon the addition of a liquid component oraqueous buffer. In other embodiments, the solid first compound, thesolid second compound, solid buffer, and at least one solid therapeuticagent are combined first to make a solid component, wherein thecompounds are mixed together upon the addition of a liquid component. Insome embodiments, the therapeutic agent is hyaluronic acid which can beadded to the solid component in solid form or added to the liquidcomponent.

In certain embodiments, the concentration of the monomers in the aqueousis from about 1% to about 100%. In some embodiments, the dilution isused to adjust the viscosity of the monomer dilution. In certainembodiments, the concentration of a monomer in the aqueous buffer isabout 1%, about 2%, about 5%, about 10%, about 15%, about 20%, about25%, about 30%, about 35%, about 40%, about 45%, about 50%, about 55%,about 60%, about 65%, about 70%, about 75%, about 80%, about 85%, about90%, about 95%, or about 100%.

In some embodiments, the electrophilic and nucleophilic monomers aremixed in such ratio that there is a slight excess of electrophilicgroups present in the mixture. In certain embodiments, this excess isabout 10%, about 5%, about 2%, about 1%, about 0.9%, about 0.8%, about0.7%, about 0.6%, about 0.5%, about 0.4%, about 0.3%, about 0.2%, about0.1%, or less than 0.1%.

In certain embodiments, the gelling time or curing time of thebiocompatible hydrogel polymer is controlled by the selection of thefirst and second compounds. In some embodiments, the concentration ofnucleophilic or electrophilic groups in the first or second compoundinfluences the gelling time of the pre-formulation. In certainembodiments, temperature influences the gelling time of thepre-formulation. In some embodiments, the type of aqueous bufferinfluences the gelling time of the pre-formulation. In certainembodiments, the concentration of the aqueous buffer influences thegelling time of the pre-formulation. In some embodiments, thenucleophilicity and/or electrophilicity of the nucleophilic andelectrophilic groups of the monomers influences the gelling time of thepre-formulation.

In some embodiments, the gelling time or curing time of thebiocompatible hydrogel polymer is controlled by the pH of the aqueousbuffer. In certain embodiments, the gelling time is between about 20seconds and 10 minutes. In some embodiments, the gelling time is lessthan 30 minutes, less than 20 minutes, less than 10 minutes, less than 5minutes, less than 4.8 minutes, less than 4.6 minutes, less than 4.4minutes, less than 4.2 minutes, less than 4.0 minutes, less than 3.8minutes, less than 3.6 minutes, less than 3.4 minutes, less than 3.2minutes, less than 3.0 minutes, less than 2.8 minutes, less than 2.6minutes, less than 2.4 minutes, less than 2.2 minutes, less than 2.0minutes, less than 1.8 minutes, less than 1.6 minutes, less than 1.4minutes, less than 1.2 minutes, less than 1.0 minutes, less than 0.8minutes, less than 0.6 minutes, or less than 0.4 minutes. In certainembodiments, the pH of the aqueous buffer is from about 5 to about 9.5.In some embodiments, the pH of the aqueous buffer is from about 7.0 toabout 9.5. In specific embodiments, the pH of the aqueous buffer isabout 8. In some embodiments, the pH of the aqueous buffer is about 5,about 5.5, about 6.0, about 6.5, about 6.6, about 6.7, about 6.8, about6.9, about 7.0, about 7.1, about 7.2, about 7.3, about 7.4, about 7.5,about 7.6, about 7.8, about 7.9, about 8.0, about 8.1 about 8.2 about8.3, about 8.4, about 8.5, about 9.0, or about 9.5.

In some embodiments, the gelling time or curing time of thebiocompatible hydrogel polymer is controlled by the pH provided by thebuffer component. In certain embodiments, the gelling time is betweenabout 20 seconds and 10 minutes. In some embodiments, the gelling timeis less than 30 minutes, less than 20 minutes, less than 10 minutes,less than 5 minutes, less than 4.8 minutes, less than 4.6 minutes, lessthan 4.4 minutes, less than 4.2 minutes, less than 4.0 minutes, lessthan 3.8 minutes, less than 3.6 minutes, less than 3.4 minutes, lessthan 3.2 minutes, less than 3.0 minutes, less than 2.8 minutes, lessthan 2.6 minutes, less than 2.4 minutes, less than 2.2 minutes, lessthan 2.0 minutes, less than 1.8 minutes, less than 1.6 minutes, lessthan 1.4 minutes, less than 1.2 minutes, less than 1.0 minutes, lessthan 0.8 minutes, less than 0.6 minutes, or less than 0.4 minutes. Incertain embodiments, the pH provided by the buffer is from about 5 toabout 9.5. In some embodiments, the pH provided by the buffer is fromabout 7.0 to about 9.5. In specific embodiments, the pH provided by thebuffer is about 8. In some embodiments, the pH of the aqueous buffer isabout 5, about 5.5, about 6.0, about 6.5, about 6.6, about 6.7, about6.8, about 6.9, about 7.0, about 7.1, about 7.2, about 7.3, about 7.4,about 7.5, about 7.6, about 7.8, about 7.9, about 8.0, about 8.1 about8.2 about 8.3, about 8.4, about 8.5, about 9.0, or about 9.5.

In certain embodiments, the gelling time or curing time of thebiocompatible hydrogel polymer is controlled by the type of buffer. Insome embodiments, the aqueous buffer is a physiologically acceptablebuffer. In some embodiments, a solid buffer is used in thepre-formulation and becomes an aqueous buffer after the addition of aliquid component. In certain embodiments, an aqueous buffer is used inthe pre-formulation. In certain embodiments, aqueous buffers include,but are not limited to, aqueous saline solutions, phosphate bufferedsaline, borate buffered saline, a combination of borate and phosphatebuffers wherein each component is dissolved in separate buffers,N-2-Hydroxyethylpiperazine-N′-2-hydroxypropanesulfonic acid (HEPES),3-(N-Morpholino) propanesulfonic acid (MOPS),2-([2-Hydroxy-1,1-bis(hydroxymethyl)ethyl]amino)ethanesulfonic acid(TES), 3-[N-tris(Hydroxy-methyl)ethylamino]-2-hydroxyethyl]-1-piperazinepropanesulfonic acid (EPPS),Tris[hydroxymethyl]-aminomethane (THAM), and Tris[hydroxymethyl]methylaminomethane (TRIS). In some embodiments, the thiol-ester chemistry(e.g., ETTMP nucleophile with SGA or SG electrophile) is performed inborate buffer. In certain embodiments, the amine-ester chemistry (NH2 orAA nucleophile with SGA or SG electrophile) is performed in phosphatebuffer.

In certain embodiments, the first compound and the second compound donot react with the therapeutic agent during formation of thebiocompatible hydrogel polymer. In some embodiments, the therapeuticagent remains unchanged after polymerization of the first and secondcompounds (i.e., monomers). In certain embodiments, the therapeuticagent does not change the properties of the hydrogel polymer. In someembodiments, the physiochemical properties of the therapeutic agent andthe hydrogel polymer formulation are not affected by the polymerizationof the monomers.

In some embodiments, the hydrogel polymer formulations further comprisea viscosity enhancer. Examples of viscosity enhancer include, but arenot limited to, hydroxyethylcellulose, hydroxypropylcellulose,methylcellulose, polyvinylcellulose, polyvinylpyrrolidone.

Area of for Treatment—Target Sites

In certain embodiments, the target site is inside a mammal. In someembodiments, the target site is inside a human being. In certainembodiments, the target site is on the human body. In some embodiments,the target site is accessible through surgery. In certain embodiments,the target site is accessible through minimally invasive surgery. Insome embodiments, the target site is accessible through an endoscopicdevice. In certain embodiments, the target site is a wound on the skinof a mammal. In other embodiments, the target site is in a joint or on abone of an animal.

In some embodiments, a pre-formulation or a biocompatible hydrogelpolymer is used as a sealant or adhesive with or without a therapeuticagent. In certain embodiments, the pre-formulation or biocompatiblehydrogel polymer is used to seal a wound on a mammal. In otherembodiments, the pre-formulation or biocompatible hydrogel polymer isused to fill cavities in the human body, e.g., in a joint space to forma gel cushion.

Delivery of the Hydrogel Formulation to a Target Site

In some embodiments, the pre-formulation is delivered as a biocompatibleformulation to a target site through a catheter or a needle to form abiocompatible hydrogel polymer at the target site. In certainembodiments, the needle or catheter is attached or part of a deliverydevice.

In other embodiments, the formulation is delivered to the target site inor on the mammal using a syringe and needle. In some embodiments, adelivery device is used to deliver the pre-formulation to the targetsite. In some embodiments, the needle has an outer diameter of about 4mm, about 3.8 mm, about 3.6 mm, about 3.4 mm, about 3.2 mm, about 3.0mm, about 2.8 mm, about 2.6 mm, about 2.4 mm, about 2.2 mm, about 2.0mm, about 1.8 mm, about 1.6 mm, about 1.4 mm, about 1.2 mm, about 1.0mm, about 0.8 mm, or about 0.6 mm. In preferred embodiments, the needlehas an outer diameter of about 1.2 mm or less. In certain embodiments,the viscosity of the pre-formulation is close to the viscosity of waterwhen delivering the mixture to the site of the tumor through thecatheter. In some embodiments, the pre-formulation forming thebiocompatible hydrogel further comprises a pharmaceutically acceptableviscosity enhancer to ensure that the pre-formulation stays in place atthe target site during the gelling process.

In certain embodiments, between 1 and 3 mL of the pre-formulationoptionally comprising a therapeutic agent is delivered to a target site.In some embodiments, about 12 mL, about 11 mL, about 10 mL, about 9 mL,about 8 mL, about 7.5 mL, about 7.0 mL, about 6.5 mL, about 6.0 mL,about 5.5 mL, about 5.0 mL, about 4.5 mL, about 4.0 mL, about 3.5 mL,about 3.0 mL, about 2.5 mL, about 2.0 mL, about 1.5 mL, about 1.0 mL,about 0.5 mL, about 0.2 mL, about 0.1 mL, about 0.05 mL or about 0.01 mLpre-formulation optionally comprising a therapeutic agent is deliveredto a target site. In certain embodiments, less than 12 mL, less than 11mL, less than 10 mL, less than 9 mL, less than 8 mL, less than 7.5 mL,less than 7.0 mL, less than 6.5 mL, less than 6.0 mL, less than 5.5 mL,less than 5.0 mL, less than 4.5 mL, less than 4.0 mL, less than 3.5 mL,less than 3.0 mL, less than 2.5 mL, less than 2.0 mL, less than 1.5 mL,less than 1.0 mL, less than 0.5 mL, less than 0.2 mL, less than 0.1 mL,less than 0.05 mL, or less than 0.01 mL pre-formulation optionallycomprising a therapeutic agent is delivered to a target site. In certainembodiments, about 0.05 to 5 mL pre-formulation optionally comprising atherapeutic agent is delivered to a target site.

In some embodiments, the gelling time of the biocompatible hydrogelpolymer is set according to the preference of the doctor delivering thehydrogel polymer mixture to a target site. In most instances, aphysician delivers the hydrogel polymer mixture to the target within 15to 30 seconds. In some embodiments, the hydrogel polymer mixture gelsafter delivery at the target site, covering the target site.

In some embodiments, the gelling time or curing time of thebiocompatible hydrogel polymer is controlled by the pH of the aqueousbuffer. In certain embodiments, the gelling time is between about 20seconds and 10 minutes. In preferred embodiments, the gelling time isabout 90 seconds. In some embodiments, the gelling time is less than 120minutes, less than 90 minutes, less than 60 minutes, less than 50minutes, less than 40 minutes, less than 30 minutes, less than 20minutes, less than 10 minutes, less than 9 minutes, less than 8 minutes,less than 7 minutes, less than 6 minutes, less than 5 minutes, less than4.8 minutes, less than 4.6 minutes, less than 4.4 minutes, less than 4.2minutes, less than 4.0 minutes, less than 3.8 minutes, less than 3.6minutes, less than 3.4 minutes, less than 3.2 minutes, less than 3.0minutes, less than 2.8 minutes, less than 2.6 minutes, less than 2.4minutes, less than 2.2 minutes, less than 2.0 minutes, less than 1.8minutes, less than 1.6 minutes, less than 1.5 minutes, less than 1.4minutes, less than 1.2 minutes, less than 1.0 minutes, less than 0.8minutes, less than 0.6 minutes, or less than 0.4 minutes. In certainembodiments, the gelling time is more than 120 minutes, more than 90minutes, more than 60 minutes, more than 50 minutes, more than 40minutes, more than 30 minutes, more than 20 minutes, more than 10minutes, more than 9 minutes, more than 8 minutes, more than 7 minutes,more than 6 minutes, more than 5 minutes, more than 4.8 minutes, morethan 4.6 minutes, more than 4.4 minutes, more than 4.2 minutes, morethan 4.0 minutes, more than 3.8 minutes, more than 3.6 minutes, morethan 3.4 minutes, more than 3.2 minutes, more than 3.0 minutes, morethan 2.8 minutes, more than 2.6 minutes, more than 2.4 minutes, morethan 2.2 minutes, more than 2.0 minutes, more than 1.8 minutes, morethan 1.6 minutes, more than 1.5 minutes, more than 1.4 minutes, morethan 1.2 minutes, more than 1.0 minutes, more than 0.8 minutes, morethan 0.6 minutes, or more than 0.4 minutes. In some embodiments, thegelling time is about 120 minutes, about 90 minutes, about 60 minutes,about 50 minutes, about 40 minutes, about 30 minutes, about 20 minutes,about 10 minutes, about 9 minutes, about 8 minutes, about 7 minutes,about 6 minutes, about 5 minutes, about 4.8 minutes, about 4.6 minutes,about 4.4 minutes, about 4.2 minutes, about 4.0 minutes, about 3.8minutes, about 3.6 minutes, about 3.4 minutes, about 3.2 minutes, about3.0 minutes, about 2.8 minutes, about 2.6 minutes, about 2.4 minutes,about 2.2 minutes, about 2.0 minutes, about 1.8 minutes, about 1.6minutes, about 1.5 minutes, about 1.4 minutes, about 1.2 minutes, about1.0 minutes, about 0.8 minutes, about 0.6 minutes, or about 0.4 minutes.

In some embodiments, the gelling time or curing time of thebiocompatible hydrogel polymer is controlled by the pH provided by thebuffer component. In certain embodiments, the gelling time is betweenabout 20 seconds and 10 minutes. In preferred embodiments, the gellingtime is about 90 seconds. In some embodiments, the gelling time is lessthan 120 minutes, less than 90 minutes, less than 60 minutes, less than50 minutes, less than 40 minutes, less than 30 minutes, less than 20minutes, less than 10 minutes, less than 9 minutes, less than 8 minutes,less than 7 minutes, less than 6 minutes, less than 5 minutes, less than4.8 minutes, less than 4.6 minutes, less than 4.4 minutes, less than 4.2minutes, less than 4.0 minutes, less than 3.8 minutes, less than 3.6minutes, less than 3.4 minutes, less than 3.2 minutes, less than 3.0minutes, less than 2.8 minutes, less than 2.6 minutes, less than 2.4minutes, less than 2.2 minutes, less than 2.0 minutes, less than 1.8minutes, less than 1.6 minutes, less than 1.5 minutes, less than 1.4minutes, less than 1.2 minutes, less than 1.0 minutes, less than 0.8minutes, less than 0.6 minutes, or less than 0.4 minutes. In certainembodiments, the gelling time is more than 120 minutes, more than 90minutes, more than 60 minutes, more than 50 minutes, more than 40minutes, more than 30 minutes, more than 20 minutes, more than 10minutes, more than 9 minutes, more than 8 minutes, more than 7 minutes,more than 6 minutes, more than 5 minutes, more than 4.8 minutes, morethan 4.6 minutes, more than 4.4 minutes, more than 4.2 minutes, morethan 4.0 minutes, more than 3.8 minutes, more than 3.6 minutes, morethan 3.4 minutes, more than 3.2 minutes, more than 3.0 minutes, morethan 2.8 minutes, more than 2.6 minutes, more than 2.4 minutes, morethan 2.2 minutes, more than 2.0 minutes, more than 1.8 minutes, morethan 1.6 minutes, more than 1.5 minutes, more than 1.4 minutes, morethan 1.2 minutes, more than 1.0 minutes, more than 0.8 minutes, morethan 0.6 minutes, or more than 0.4 minutes. In some embodiments, thegelling time is about 120 minutes, about 90 minutes, about 60 minutes,about 50 minutes, about 40 minutes, about 30 minutes, about 20 minutes,about 10 minutes, about 9 minutes, about 8 minutes, about 7 minutes,about 6 minutes, about 5 minutes, about 4.8 minutes, about 4.6 minutes,about 4.4 minutes, about 4.2 minutes, about 4.0 minutes, about 3.8minutes, about 3.6 minutes, about 3.4 minutes, about 3.2 minutes, about3.0 minutes, about 2.8 minutes, about 2.6 minutes, about 2.4 minutes,about 2.2 minutes, about 2.0 minutes, about 1.8 minutes, about 1.6minutes, about 1.5 minutes, about 1.4 minutes, about 1.2 minutes, about1.0 minutes, about 0.8 minutes, about 0.6 minutes, or about 0.4 minutes.

In certain embodiments, the pH of the aqueous buffer is from about 5.0to about 9.5. In some embodiments, the pH of the aqueous buffer is fromabout 6.0 to about 8.5. In specific embodiments, the pH of the aqueousbuffer is about 8.0. In some embodiments, the pH is about 5, about 5.1,about 5.2, about 5.3, about 5.4, about 5.5, about 5.6, about 5.7, about5.8, about 5.9, about 6, about 6.1, about 6.2, about 6.3, about 6.4,about 6.5, about 6.6, about 6.7, about 6.8, about 6.9, about 7, about7.1, about 7.2, about 7.3, about 7.4, about 7.5, about 7.6, about 7.7,about 7.8, about 7.9, about 8, about 8.1, about 8.2, about 8.3, about8.4, about 8.5, about 8.6, about 8.7, about 8.9, about 9, about 9.1about 9.2, about 9.3, about 9.4, or about 9.5.

In certain embodiments, the pH provided by the buffer is from about 5.0to about 9.5. In some embodiments, the pH provided by the buffer is fromabout 6.0 to about 8.5. In specific embodiments, the pH provided by thebuffer is about 8.0. In some embodiments, the pH is about 5, about 5.1,about 5.2, about 5.3, about 5.4, about 5.5, about 5.6, about 5.7, about5.8, about 5.9, about 6, about 6.1, about 6.2, about 6.3, about 6.4,about 6.5, about 6.6, about 6.7, about 6.8, about 6.9, about 7, about7.1, about 7.2, about 7.3, about 7.4, about 7.5, about 7.6, about 7.7,about 7.8, about 7.9, about 8, about 8.1, about 8.2, about 8.3, about8.4, about 8.5, about 8.6, about 8.7, about 8.9, about 9, about 9.1about 9.2, about 9.3, about 9.4, or about 9.5.

In certain embodiments, the gelling time or curing time of thebiocompatible hydrogel polymer is controlled by the selection of thefirst and second compounds. In some embodiments, the concentration ofnucleophilic or electrophilic groups in the first or second compoundinfluences the gelling time of the pre-formulation.

In some embodiments, curing of the biocompatible hydrogel polymer isverified post-administration. In certain embodiments, the verificationis performed in vivo at the delivery site. In other embodiments, theverification is performed ex vivo. In some embodiments, curing of thebiocompatible hydrogel polymer is verified visually. A lack of flow ofthe biocompatible hydrogel polymer indicates that the biocompatiblehydrogel polymer has gelled and the hydrogel is sufficiently cured. Infurther embodiments, curing of the biocompatible hydrogel polymer isverified by evaluation of the residue in the delivery device, forinstance the residue in the catheter of the bronchoscope or otherendoscopic device, or the residue in the syringe used to deliver thebiocompatible hydrogel polymer. In other embodiments, curing of thebiocompatible hydrogel polymer is verified by depositing a small sample(e.g., ˜1 mL) on a piece of paper or in a small vessel and subsequentevaluation of the flow characteristics after the gelling time haspassed.

In some embodiments, the pre-formulation optionally comprising one ormore therapeutic agents is delivered to the target site so that thepre-formulation mostly covers the target site. In certain embodiments,the pre-formulation substantially covers an exposed portion of diseasedtissue. In some embodiments, the pre-formulation does not spread to anyother location intentionally. In some embodiments, the pre-formulationsubstantially covers diseased tissue and does not significantly coverhealthy tissue. In certain embodiments, the biocompatible hydrogelpolymer does not significantly cover healthy tissue. In someembodiments, pre-formulation gels over the target site and thoroughlycovers diseased tissue. In some embodiments, the biocompatible hydrogelpolymer adheres to tissue.

Bioabsorbance of the Hydrogel

In some embodiments, the biocompatible hydrogel polymer is abioabsorbable polymer. In certain embodiments, the biocompatiblehydrogel polymer is bioabsorbed within about 5 to 30 days. In someembodiments, the biocompatible hydrogel polymer is bioabsorbed withinabout 30 to 180 days. In preferred embodiments, the biocompatiblehydrogel polymer is bioabsorbed within about 1 to 70 days. In someembodiments the biocompatible hydrogel polymer is bioabsorbed withinabout 365 days, 180 days, about 150 days, about 120 days, about 90 days,about 80 days, about 70 days, about 60 days, about 50 days, about 40days, about 35 days, about 30 days, about 28 days, about 21 days, about14 days, about 10 days, about 7 days, about 6 days, about 5 days, about4 days, about 3 days, about 2 days, or about 1 day. In certainembodiments the biocompatible hydrogel polymer is bioabsorbed withinless than 365 days, 180 days, less than 150 days, less than 120 days,less than 90 days, less than 80 days, less than 70 days, less than 60days, less than 50 days, less than 40 days, less than 35 days, less than30 days, less than 28 days, less than 21 days, less than 14 days, lessthan 10 days, less than 7 days, less than 6 days, less than 5 days, lessthan 4 days, less than 3 days, less than 2 days, or less than 1 day. Insome embodiments the biocompatible hydrogel polymer is bioabsorbedwithin more than 365 days, 180 days, more than 150 days, more than 120days, more than 90 days, more than 80 days, more than 70 days, more than60 days, more than 50 days, more than 40 days, more than 35 days, morethan 30 days, more than 28 days, more than 21 days, more than 14 days,more than 10 days, more than 7 days, more than 6 days, more than 5 days,more than 4 days, more than 3 days, more than 2 days, or more than 1day. In some embodiments, the biocompatible hydrogel polymer issubstantially non-bioabsorbable.

The biocompatible hydrogel polymer is slowly bioabsorbed, dissolved, andor excreted. In some instances, the rate of bioabsorption is controlledby the number of ester groups in the biocompatible and/or biodegradablehydrogel polymer. In other instances, the higher the concentration ofester units is in the biocompatible hydrogel polymer, the longer is itslifetime in the body. In further instances, the electron density at thecarbonyl of the ester unit controls the lifetime of the hydrogel polymerin the body. In certain instances, biocompatible hydrogel polymerswithout ester groups are essentially not biodegradable. In additionalinstances, the molecular weight of the first and second compoundscontrols the lifetime of the hydrogel polymer in the body. In furtherinstances, the number of ester groups per gram of polymer controls thelifetime of the hydrogel polymer in the body.

In some instances, the lifetime of the hydrogel polymer can be estimatedusing a model, which controls the temperature and pH at physiologicallevels while exposing the hydrogel polymer to a buffer solution. Incertain instances, the biodegradation of the hydrogel polymer issubstantially non-enzymatic degradation.

In some embodiments, the selection of reaction conditions determines thedegradation time of the hydrogel polymer. In certain embodiments, theconcentration of the first compound and second compound monomersdetermines the degradation time of the resulting hydrogel polymer. Insome instances, a higher monomer concentration leads to a higher degreeof cross-linking in the resulting hydrogel polymer. In certaininstances, more cross-linking leads to a later degradation of thehydrogel polymer.

In certain embodiments, the composition of the linker in the firstand/or second compound influences the speed of degradation of theresulting hydrogel polymer. In some embodiments, the more ester groupsare present in the hydrogel polymer, the faster the degradation of thehydrogel polymer. In certain embodiments, the higher the concentrationof mercaptopropionate (ETTMP), acetate amine (AA), glutarate orsuccinate (SG or SS) monomers, the faster the rate of degradation.

Wound Patch or Joint Spacer in the Treatment of Veterinary Disease

In some embodiments, the pre-formulation described herein is deliveredto a target site on or in an animal. In certain embodiments, thepre-formulation is delivered to a target site in a joint. In someembodiments, the pre-formulation forms a biocompatible hydrogel polymerinside a joint. In certain embodiments, the pre-formulation forms asticky biocompatible polymer to seal a wound on or in an animal. In someembodiments, the pre-formulation forms a suture. In certain embodiments,the wound patch, joint spacer, or suture gels at least in part at thetarget site in or on the animal. In some embodiments, the wound patch,joint spacer, or suture polymerizes at least in part at a target site.In some embodiments, the wound patch, joint spacer, or suture adheres atleast partially to the target site.

In certain embodiments, the pre-formulation is used as a “liquid suture”or as a drug delivery platform to transport medications directly to thetargeted site in or on the animal or human. In some embodiments thetarget site is a joint, a wound or the navicular bone. In someembodiments, the spreadability, viscosity, optical clarity, and adhesiveproperties of the pre-formulation are optimized to create materialsideal as liquid sutures for the treatment of veterinary diseases. Incertain embodiments, the gel time is controlled from 50 seconds to 15minutes.

In some embodiments, a method of treating wounds of a mammal bydelivering a liquid polyglycol-based, fully synthetic, biocompatibleformulation formed by adding a liquid component to the solidpolyglycol-based, fully synthetic, pre-formulation to a target site ofthe wound of the mammal, wherein the liquid polyglycol-based, fullysynthetic, biocompatible formulation gels at the target site of thewound. In another aspect, provided herein, is a method of treatingarthritis in a mammal by by delivering a liquid polyglycol-based, fullysynthetic, biocompatible hydrogel polymer formed by adding a liquidcomponent to the solid polyglycol-based, fully synthetic,pre-formulation into a target site in a joint space, wherein the liquidpolyglycol-based, fully synthetic, biocompatible formulation gels at thetarget site in the joint space. In some embodiments, the mammal is ahuman. In other embodiments, the mammal is an animal. In a furtheraspect, provided herein is a method of treating navicular disease in ahorse by by delivering a liquid polyglycol-based, fully synthetic,biocompatible formulation formed by adding a liquid component to thesolid polyglycol-based, fully synthetic, pre-formulation to a targetsite in a hoof of the horse, wherein the liquid polyglycol-based, fullysynthetic, biocompatible formulation gels at the target site in the hoofof the horse.

In some embodiments, a method of treating wounds of a mammal bydelivering a liquid biocompatible formulation formed by adding a liquidcomponent to the solid pre-formulation to a target site of the wound ofthe mammal, wherein the liquid biocompatible formulation gels at thetarget site of the wound. In another aspect, provided herein, is amethod of treating arthritis in a mammal by by delivering a liquidbiocompatible hydrogel polymer formed by adding a liquid component tothe solid pre-formulation into a target site in a joint space, whereinthe liquid biocompatible formulation gels at the target site in thejoint space. In some embodiments, the mammal is a human. In otherembodiments, the mammal is an animal. In a further aspect, providedherein is a method of treating navicular disease in a horse by bydelivering a liquid, biocompatible formulation formed by adding a liquidcomponent to the solid pre-formulation to a target site in a hoof of thehorse, wherein the liquid biocompatible formulation gels at the targetsite in the hoof of the horse.

Control of Release Rate of a Therapeutic Agent

In some embodiments, the biocompatible hydrogel polymer slowly deliversa therapeutic agent to a target site by diffusion and/or osmosis overtime ranging from hours to days. In certain embodiments, the drug isdelivered directly to the target site. In some embodiments, theprocedure of delivering a biocompatible hydrogel polymer comprising atherapeutic agent to a target site is repeated several times, if needed.In other embodiments, the therapeutic agent is released from thebiocompatible hydrogel polymer through biodegradation of the hydrogelpolymer. In some embodiments, the therapeutic agent is released througha combination of diffusion, osmosis, and/or hydrogel degradationmechanisms. In certain embodiments, the release profile of thetherapeutic agent from the hydrogel polymer is unimodal. In someembodiments, the release profile of the therapeutic agent from thehydrogel polymer is bimodal. In certain embodiments, the release profileof the therapeutic agent from the hydrogel polymer is multimodal.

In some embodiments, the therapeutic agent is released from thebiocompatible hydrogel polymer though diffusion or osmosis. In certainembodiments, the therapeutic agent is substantially released from thebiocompatible hydrogel polymer within 180 days. In some embodiments, thetherapeutic agent is substantially released from the biocompatiblehydrogel polymer within 14 days. In certain embodiments, the therapeuticagent is substantially released from the biocompatible hydrogel polymerwithin 24 hours. In some embodiments, the therapeutic agent issubstantially released from the biocompatible hydrogel polymer withinone hour. In certain embodiments, the therapeutic agent is substantiallyreleased from the biocompatible hydrogel polymer within about 180 days,about 150 days, about 120 days, about 90 days, about 80 days, about 70days, about 60 days, about 50 days, about 40 days, about 35 days, about30 days, about 28 days, about 21 days, about 14 days, about 10 days,about 7 days, about 6 days, about 5 days, about 4 days, about 3 days,about 2 days, about 1 day, about 0.5 day, about 6 hours, about 4 hours,about 2 hours, about or 1 hour. In some embodiments, the therapeuticagent is substantially released from the biocompatible hydrogel polymerwithin more than 180 days, more than 150 days, more than 120 days, morethan 90 days, more than 80 days, more than 70 days, more than 60 days,more than 50 days, more than 40 days, more than 35 days, more than 30days, more than 28 days, more than 21 days, more than 14 days, more than10 days, more than 7 days, more than 6 days, more than 5 days, more than4 days, more than 3 days, more than 2 days, more than 1 day, more than0.5 day, more than 6 hours, more than 4 hours, more than 2 hours, morethan or 1 hour. In certain embodiments, the therapeutic agent issubstantially released from the biocompatible hydrogel polymer withinless than 180 days, less than 150 days, less than 120 days, less than 90days, less than 80 days, less than 70 days, less than 60 days, less than50 days, less than 40 days, less than 35 days, less than 30 days, lessthan 28 days, less than 21 days, less than 14 days, less than 10 days,less than 7 days, less than 6 days, less than 5 days, less than 4 days,less than 3 days, less than 2 days, less than 1 day, less than 0.5 day,less than 6 hours, less than 4 hours, less than 2 hours, less than or 1hour. In some embodiments, the therapeutic agent is substantiallyreleased from the biocompatible hydrogel polymer within about one day toabout fourteen days. In certain embodiments, the therapeutic agent issubstantially released from the biocompatible hydrogel polymer withinabout one day to about 70 days.

In some embodiments, the therapeutic agent is a biomolecule and therelease of the biomolecule from the hydrogel polymer is controlled bythe composition of the hydrogel polymer. In certain embodiments, thebiomolecule is released when the hydrogel polymer starts to degrade. Insome embodiments, the pore size of the hydrogel polymer is small enoughto prevent the early phase release of the biomolecule (i.e., releasebefore the degradation of the hydrogel polymer). In certain embodiments,the pore size of the hydrogel polymer is large enough to allow the earlyphase release of the biomolecule. In some embodiments, the ratio of thepore size of the hydrogel polymer to the size of the biomoleculedetermines the release rate of the biomolecule.

Exemplary Antibacterials

In some embodiments, the pre-formulation comprises an antibacterialagent as the therapeutic agent. In some embodiments, the pre-formulationcomprises an antiseptic agent. An antibacterial agent is defined as anagent that inhibits the reproduction and growth of bacteria, and includeantiseptics. In certain embodiments, the antiseptic agent is an alcohol,an aldehyde, a halogen-releasing compound, or a peroxide. In otherembodiments, the antiseptic agent is an anilide, a biguanide, abisphenol, a halophenol, a heavy metal, a phenol, a cresol or aquaternary ammonium compound. Examples of antiseptics include, but arenot limited to, Alchols like ethanol and isopropyl alchol; Aldehydeslike glutaraldehyde and formaldehyde, Halogen releasing compounds likechlorine compounds and iodine compounds; Peroxides like hydrogenperoxide, ozone, peracetic acid; Biguanides, like chlorhexidine,alexidine, and polymeric biguanides; Bisphenols like triclosan andhexachlorophene; Heavy metals like silver compounds and mercurycompounds; Quaternary ammonium compounds like benzalknoium chloride,cetrimide, methylbenzethonium chloride, benzethonium chloride,cetaalkonium chloride, cetylpyridinium chloride, and dofanium chloride.

Exemplary Antifungals

In some embodiments, the pre-formulation comprises an antifungal agentas the therapeutic agent. In certain embodiments, the antifungal agentis a polyene antifungal, an imidazole, triazole, or thiazole antifungal,a triazole antifungal, a thiazole antifungal, an allylamine derivative,or an echinocandin derivative. Examples of antifungal agents include,but are not limited to, Polyene derivatives like natamycin, rimocidin,filipin, nystatin, amphotericin B, candicin, hamycin; Imidazolederivatives like miconazole, ketoconazole, clotrimazole, econazole,omoconazole, bifonazole, butoconazole, fenticonazole, isoconazole,oxiconazole, sertaconazole, sulconazole, tioconazole; Tetrazolederivatives like fluconazole, itraconazole, isavuconazole, posaconazole,voriconzaole, terconazole, albaconazole; Thiazole derivatives likeabafungin; Allylamine derivative like terbifine, naftifine, butenafine;Echinocandin derivatives like anidulafungin, caspofungin, micafungin;Other antifungals like polygodial, benzoic acid, ciclopirox, tonaftate,undecylenic acid, flycytosine, griseofulvin, haloprogin, sodiumbicarbonate, pirctone olamine, zinc pyrithione, selenium sulfide, tar,or tea tree oil.

Exemplary Antibiotics

In some embodiments, the pre-formulation comprises an antibiotic. Incertain embodiments, the antibiotic agent is a aminoglycoside,ansamycin, carbacephem, carbapenem, cephalosporin, glycopeptide,lincosamide, lipopeptide, macrolide, monobactam, nitrofurans,penicillin, polypeptide, quinolone, sulfonamide, or tetracycline.Examples of antibiotic agents include, but are not limited to,Aminoglycoside derivatives like amikacin, gentamicin, kanamycin,neomycin, netilmicin, tobramicin, paromomycin; Ansamycin derivativeslike geldanamycin, herbimycin; Carbacephem derivatives like loracarbef,Carbapenem derivatives like ertapenem, doripenem, imipenem, meropenem;Cephalosporin derivatives like cefadroxil, cefazolin, cefalotin,cefalexin, cefaclor, cefamandole, cefoxitin, cefprozil, cefuroxime,cefixime, cefdinir, cefditoren, cefoperazone, cefotaxime, cefpodoxime,ceftazidime, ceftibuten, ceftizoxime, ceftriaxone, cefepime,ceftobiprole; Glycopeptide derivatives like teicoplanin, vancomycin,telavancin; Lincosamides like clindamycin, lincomycin; Lipopeptidederivatives like daptomycin; Macrolide derivatives like azithromycin,clarithromycin, dirithromycin, erythromycin, roxithromycin,troleandomycin; telithreomycin, spectinomycin; Monobactam derivativeslike aztreonam; Nitrofuran derivatives like furazolidone,nitrofurantoin; Penicillin derivatives like amoxicillin, ampicillin,azlocillin, carbinicillin, cloxacillin, dicloxacillin, flucloxacillin,mezlocillin, methicillin, nafcillin, oxacillin, penicillin G, penicillinV, piperacillin, temocillin, ticarcillin; Penicillin combinations likeamoxicillin/clavulanate, ampicillin/sulbactam, piperacillin/tazobactam,ticarcillin/clavulanate; Polypeptide derivatives like bacitracin,colistin, polymyxin B; Quinolone derivatives like ciprofloxacin,enoxacin, gatifloxacin, levofloxacin, lomefloxacin, moxifloxacin,nalidixic acid, norfloxacin, ofloxacin, trovafloxacin, grepafloxacin,sparfloxacin, temafloxacin, danofloxacin, difloxacin, enrofloxacin,ibafloxacin, marbofloxacin, orbifloxacin, sarafloxacin; Sulfonamidederivatives like mafenide, sulfonamidochrysoidine, sulfacetamide,sulfadiazine, silver sulfadiazine, sulfamethoxazole, sulfanilimide,sulfasalazine, sulfisoxazole, trimethoprim,trimethoprim/sulfamethoxazole; Tetracyclin derivatives likedemeclocycline, doxycycline, minocycline, oxytetracycline, tetracycline;Derivatives against mycobacteria like clofazimine, dapsone, capreomycin,cycloserine, ethambutol, ethioamide, isoniazid, pyrazinamide, rifampin,refampicin, rifabutin, rifapentine, streptomycin; or other antibioticagents like arsphenamine, chloramphenicol, fosfomycin, fusidic acid,linezolid, metronidazole, mupirocin, platensimycin,quinupristin/dalfopristin, rifaximin, thiampheniol, tigecycline,timidazole.

Exemplary Antiviral Agents

In some embodiments, the pre-formulation comprises an antiviral agent.In certain embodiments, the antiviral agent is a nucleoside reversetranscriptase inhibitor, a non-nucleoside reverse transcriptaseinhibitor, a fusion inhibitor, an integrase inhibitor, a nucleosideanalog, a protease inhibitor, a reverse transcriptase inhibitor.Examples of antiviral agents include, but are not limited to, abacavir,aciclovir, acyclovir, adefovir, amantadine, amprenavir, ampligen,arbidol, atazanavir, boceprevir, cidofovir, darunavir, delavirdine,didanosine, docosanol, edoxudine, efavirenz, emtricitabine, enfuvirtide,entecavir, famciclovir, fomivirsen, fosamprenavir, foscarnet, fosfonet,ganciclovir, ibacitabine, immunovir, idoxuridine, imiquimod, indinavir,inosine, interferon type III, interferon type II, interferon type I,interferon, lamivudine, lopinavir, loviride, maraviroc, moroxydine,methisazone, nelfinavir, nevirapine, nexavir, oseltamivir, peginterferonalfa-2a, penciclovir, peramivir, pleconaril, podophyllotoxin,raltegravir, ribavirin, rimantadine, ritonavir, pyramidine, saquinavir,stavudine, tea tree oil, tenofovir, tenofovir disoproxil, tipranavir,trifluridine, trizivir, tromantadine, truvada, valaciclovir (Valtrex),valganciclovir, vicriviroc, vidarabine, viramidine, zalcitabine,zanamivir, zidovudine.

Exemplary Immunosuppressive Agents

In some embodiments, the pre-formulation comprises an immunosuppressiveagent. In certain embodiments, the immunosuppressive agent is acalcinuerin inhibitor, mTor inhibitor, an anti-proliferative agent(e.g., an alkylating agent or an antimetabolite), a glucocorticosteroid,an antibody, or an agent acting on immunophilins. Examples ofimmunosuppressive agents include, but are not limited to, Calcineurininhibitors like ciclosporin, tacrolimus; mTOR inhibitors like sirolimus,everolimus; Anti-proliferatives like azathioprine, mycophenolic acid;Corticosteroids like prednisolone, hydrocortisone; Monoclonalanti-IL-2Rα receptor antibodies like basiliximab, daclizumab; Polyclonalanti-T-cell antibodies like anti-thymocyte globulin (ATG),anti-lymphocyte globulin (ALG); Monoclonal anti-CD20 antibodies likerituximab; Interleukin inhibitors like daclizumab, basiliximab,anakinra, rilonacept, ustekinumab, mepolizumab, tocilizumab,canakinumab, briakinumab; Tumor necrosis factor alpha (TNF-α) inhibitorslike etanercept, infliximab, afelimomab, adalimumab, certolizumab pegol,golimumab; Selective immunosuppressants like muromonab-CD3,antilymphocyte immunoglobulin (horse), antithymocyte immunoglobulin(rabbit), mycophenolic acid, sirolimus, leflunomide, alefacept0,everolimus, gusperimus, efalizumab, abetimus, natalizumab, abatacept,eculizumab, belimumab, fingolimod, belatacept; or Otherimmunosuppressants like azathioprine, thalidomide, methotrexate,lenalidomide

Exemplary Hemostasis Agents

In some embodiments, the pre-formulation comprises a hemostasis agent(or antihemorrhagic agent). In certain embodiments, the hemostasis agentis an antifibrinolytic (amino acid or proteinase inhibitor), a vitaminK, fibrinogen, a local hemostatic, or a blood coagulation factor.Examples of hemostasis agents include, but are not limited to, Aminoacids like aminocaproic acid, tranexamic acid, aminomethylbenzoic acid;Proteinase inhibitors like aprotinin, alfal antitrypsin, C1-inhibitor,camostat; Vitamin K like phytomenadione, menadione; Fibrinogen likeHuman fibrinogen; Local hemostatics like absorbable gelatin sponge,oxidized cellulose, tetragalacturonic acid hydroxymethylester,adrenalone, thrombin, collagen, calcium alginate, epinephrine, humanfibrinogen; Blood coagulation factors like coagulation factor IX, II,VII and X in combination, coagulation factor VIII, factor VIII inhibitorbypassing activity, coagulation factor IX, coagulation factor VII, vonWillebrand factor and coagulation factor VIII in combination,coagulation factor XIII, eptacog alfa, nonacog alfa, thrombin; Othersystemic hemostatics like etamsylate, carbazochrome, batroxobin,romiplostim, eltrombopag.

Exemplary Anti-Inflammatory Agents

In some embodiments, the pre-formulation comprises an anti-inflammatoryagent. In certain embodiments, the anti-inflammatory agent is anon-steroidal anti-inflammatory agent. In other embodiments, theanti-inflammatory agent is a glucocorticosteroid. In some embodiments,the non-steroidal anti-inflammatory agent is a butylpyrazolidine, anacetic acid derivative, oxicam, propionic acid derivative, fenamate, orcoxib. Examples of anti-inflammatory agents include, but are not limitedto, Butylpyrazolidines like phenylbutazone, mofebutazone,oxyphenbutazone, clofezone, kebuzone; Acetic acid derivatives andrelated substances like indometacin, sulindac, tolmetin, zomepirac,diclofenac, alclofenac, bumadizone, etodolac, lonazolac, fentiazac,acemetacin, difenpiramide, oxametacin, proglumetacin, ketorolac,aceclofenac, bufexamac, indometacin combinations, diclofenaccombinations; Oxicams like piroxicam, tenoxicam, droxicam, lornoxicam,meloxicam; Propionic acid derivatives like ibuprofen, naproxen,ketoprofen, fenoprofen, fenbufen, benoxaprofen, suprofen, pirprofen,flurbiprofen, indoprofen, tioprofenoic acid, oxaprozin, ibuproxam,dexibuprofen, flunoxaprofen, alminoprofen, dexketoprofen, naproxcinod;Fenamates like mefenamic acid, tolfenamic acid, flufenamic acid,meclofenamic acid; Coxibs like celecoxib, rofecoxib, valdecoxib,parecoxib, etoricoxib, lumiracoxib; Other antiinflammatory andantirheumatic agents like nabumetone, niflumic acid, azapropazone,glucosamine, benzydamine, glucosaminoglycan polysulfate, proquazone,orgotein, nimesulide, feprazone, diacerein, morniflumate, tenidap,oxaceprol, chondroitin sulfate; Corticosteroids like theMineralocorticoids aldosterone, fludrocortisones, desoxycortone, and theGlucocorticoids betamethasone, dexamethasone, fluocortolone,methylprednisolone, paramethasone, prednisolone, prednisone,triamcinolone, hydrocortisone, cortisone, prednylidene, rimexolone,deflazacort, cloprednol, meprednisone, cortivazol.

Exemplary Bisphosphonates

In some embodiments, the pre-formulation comprises a bisphosphonate.Examples of bisphosphonates include, but are not limited to, etidronic,clodronic acid, pamidronic acid, alendronic acid, tiludronic acid,ibandronic acid, risedronic acid, zoledronic acid.

Exemplary Analgesics and Anesthetics

In some embodiments, the pre-formulation comprises an analgesic oranesthetic agent. In certain embodiments, the analgesic or anestheticagent comprises paracetamol, an opiate, diproqualone, phenazone,cocaine, or lidocaine. In certain embodiments, the opioid is a naturalopium alkaloid, phenylpiperidine derivative, diphenylpropylaminederivative, benzomorphan derivative, oripavin derivative, or morphinanderivative. In some embodiments, the analgesic is a salicylic acidderivative, pyrazolone, or anilide. In other embodiments, the analgesicis an ergot alkaloid, corticosteroid derivative, or selective serotonin(5HT1) agonist. Examples of local anesthetics include, but are notlimited to, Esters of aminobenzoic acid like metabutethamine, procaine,tetracaine, chloroprocaine, benzocaine; Amides like bupivacaine,lidocaine, mepivacaine, prilocalne, butanilicaine, cinchocaine,etidocaine, articaine, ropivacaine, levobupivacaine, tetracaine,chloroprocaine, benzocaine; Esters of benzoic acid like cocaine; Otherlocal anesthetics like ethyl chloride, dyclonine, phenol, capsaicin.

Exemplary Proteins, Biomolecules, and Other Therapeutic Agents

In some embodiments, the pre-formulation comprises a protein or otherbiomolecule. Examples of proteins and other biomolecules include, butare not limited to abarelix, abatacept, acarbose, adalimumab,alglucosidase alfa, Antihemophilic Factor Recombinant, antithrombinrecombinant lyophilized powder for reconstitution, belatacept,belimumab, bevacizumab, botulinum toxin type A, canakinumab,certolizumab pegol, Cetrotide, cetuximab, chorionic human recombinantgonadotropin, coagulation Factor IX (recombinant), collagenaseclostridium histolyticum, conjugated estrogens, Cyanocobalamin,darbepoetin alfa, denosumab, Diphtheria and Tetanus Toxoids andAcellular Pertussis Vaccine Adsorbed, Diptheria and Tetanus Toxoids andAcellular Pertussis Vaccine Absorbed, dornase alfa, drotrecogin alfa[activated]), ecallantide, eculizumab, enfuvirtide, enoxaparin sodium,epoetin alfa, etanercept, exenatide, filgrastim, follitropin alfa,follitropin beta, Fragmin, galsulfase, gemtuzumab ozogamicin, glatirameracetate, Glucagon, golimumab, goserelin acetate, Haemophilus b ConjugateVaccine—Tetanus Toxoid Conjugate, histrelin acetate, ibritumomabtiuxetan, idursulfase, incobotulinumtoxin A, infliximab, Influenza VirusVaccine, insulin derivatives, insulin aspart, insulin glargine [rDNAorigin], insulin lispro, interferon alfacon-1, interferon beta-1a,Interferon beta-1b, ipilimumab, Japanese EncephalitisVaccine—Inactivated—Adsorbed, lanreotide acetate, laronidase, leuprolideacetate for depot suspension, leuprolide acetate, linagliptin,liraglutide, mecasermin, menotropins, methoxy polyethyleneglycol-epoetin beta, natalizumab, ofatumumab, omalizumab,onabotulinumtoxin A, palivizumab, pancrelipase, pancrelipase,panitumumab, pegaptanib, pegfilgrastim, peginterferon alfa-2a,peginterferon alfa-2b, pegloticase, pegvisomant, pentosan polysulfatesodium, pramlintide, quadrivalent human papillomavirus (types 6, 11, 16,18) recombinant vaccine, ranibizumab, rasburicase, Recombinant HumanPapillomavirus Bivalent (Types 16 and 18) Vaccine, recombinantInterferon alfa-2b, reteplase, Rituximab, romiplostim, sargramostim,secretin, sevelamer carbonate, sevelamer hydrochloride, sipuleucel-T,somatropin, somatropin [rDNA origin], teriparatide, tocilizumab,trastuzumab, triptorelin pamoate, ustekinumab, velaglucerase alfa forinjection.

In certain embodiments, the pre-formulation comprises a protein as apharmaceutically active biomolecule. Examples of proteins include, butare not limited to, octreotide, eptifibatide, desmopressin,leuprolide/leuprorelin, goserelin, ciclosporin, bivalirudin, glucagon,calcitonin, teriparatide, enfuvirtide, ecallantide, romiplostim. In someembodiments, the pre-formulation comprises a recombinant protein as apharmaceutically active biomolecule. Examples of recombinant proteinsinclude, but are not limited to, insulin, lepirudin, somatropin,aldesleukin, interferon gamma 1b, anakinra, interferon alpha 2b,interferon beta 1b, interferon beta 1a, PEG interferon alpha 2a,filgrastim, pegfilgrastim, oprelvekin, reteplase, denileukin diftitox,follitropin alfa, recFSH, thyrotropin alfa, imiglucerase, becaplermin,sargramostim, darbepoetin, erythropoietin, DNAse, Factor VIIa, FactorIX, Factor XIII, drotrecogin, alteplase, tenecteplase, moroctocog alfa(BDDrFVIII), Factor VIII-2, Factor VIII, peginteferon, ribavarin,clostridial collagenese, alglucosidase alpha2, incobotulinumtoxina,pegloticase, palifermin, galsulfase, idursulfase. In certainembodiments, the biocompatible hydrogel polymer comprises an antibody asa pharmaceutically active biomolecule. Examples of antibodies include,but are not limited to, etanercept, abciximab, gemtuzumab, rituximab,adalimumab, palivizumab, trastuzumab, bevacizumab, natalizumab,omalizumab, infliximab, alemtuzumab, efalizumab, cetuximab, golimumab,abobotulinumtoxina, canakinumab, ustekinumab, ofatumumab, certolizumabpegol, tocilizumab, denosumab, abatacept, ranibizumab, panitumumab,eculizumab, brentixumab, iplimumab, belimumab, rilonacept.

In some embodiments, the pre-formulation comprises other therapeuticagents. Examples of other therapeutic agents include, but are notlimited to, stem cells and gallium nitrate. Furthermore, othertherapeutic agents also include bitterants or aversive agents, which canbe used to prevent accidental ingestion. Examples of bitterants includedenatonium, sucrose octaacetate, brucine, and quassin.

Exemplary Lubricity Agents

In certain embodiments, the pre-formulation comprises a lubricity agent.Lubricity agents, or lubricants, are defined as substances that reducethe friction between moving surfaces. In some embodiments, lubricityagents reduce the friction between joints. In specific embodiments, thelubricity agent is hyaluronic acid. Other examples of lubricity agents,include glucosamine, chondroitin, methylsulfonylmethane (MSM),omega-3-fatty acids, hyaluronic acid, and shark cartilage.

EXAMPLES

The following specific examples are to be construed as merelyillustrative, and not limitative of the remainder of the disclosure inany way whatsoever.

The following general characteristics of the monomers and polymers areneeded to be successful for bonding to the skin without causing anyadverse effects.

Monomers Property Characteristics 1 In vivo polymerizable Could bepolymerized inside mammalian cavity or over the skin 2 Reaction mixturepH Physiological to 8.0 pH range 3 Reaction temperature Ambient to bodytemperature 4 Formulation physical Two or three component system; Mixedform immediately prior to use, may contain radiopaque agent such asbarium sulphate or iodine containing organic compounds or other knownradiopaque agents 5 Mixing time for the Few seconds (~10 sec) reactionto start 6 Gel formation time Gel formation time ranges from 10 secondsto 120 seconds, or could be as long as 30 minutes depending on theapplication 7 Solution viscosity Solution viscosity ranges from 1 to 800cps 8 Sterilization ETO to E-beam sterilizable capability 9 Localizeddelivery Ideal for localized delivery for small molecules, largemolecules and cells 10 Stability of drugs in All small molecule drugsand proteins formulation mixture studied so far have been found to bestable

Below are some adhesive polymer characteristics.

Adhesive Property Characteristics 1 Tissue adhesion Sticky formulations,physicochemical characteristics ideal for bonding to skin, bones, orother mammalian tissues 2 Polymer hardness Can be controlled from softtissues to harder cartilage like materials 3 Bioabsorption Time About 2weeks up to 10 years, or totally non-bioabsorbable 4 BiocompatibilityHighly biocompatible; passed all the subjected ISO 10993 tests 5 Polymercytotoxicity Non-cytotoxic formulations 6 Small molecule elution Smalldrug molecules elution can be controlled and thus pharmaceutical drugscould also be delivered using the formulations, if needed 7Compatibility with Highly compatible due to physiological proteins andCells pH of the polymers

For applications on-site, desired gel times are under 120 seconds.Additionally, the viscosity should be high enough to prevent excessivespreading around the target treatment area, but low enough to enter anysmall cavities at the site. Furthermore, the reaction buffers should beclose to physiological conditions. The desired degradation time andpolymer pore size will vary based on the application. The polymer shouldbe elastic and strong enough to resist fragmentation in the body.

The chemical components of the polymers are listed in Table 1. Thechemical monomers will be referred to by their abbreviations. Allmaterials were stored and handled at 20° C. unless specified. SeveralUSP grade viscosity enhancing agents were purchased from Sigma-Aldrichand were stored at 25° C. They include methylcellulose (Methocel® MC,10-25 MPA.S) abbreviated as MC; hypromellose(hydroxypropylmethylcellulose 2910) abbreviated as HPMC; and povidoneK-30 (polyvinylpyrrolidone) abbreviated as PVP. The 2% chlorhexidinesolution was stored at 5° C. and allowed to warm to room temperaturebefore use, which typically took 30 minutes. The monomers were stored at5° C. and allowed to warm to room temperature before use, whichtypically took 30 minutes. After use the contents were purged with N₂for approximately 30 seconds before sealing with parafilm and returningto 5° C. Alternately, the monomers were stored at −20° C. and allowed towarm to room temperature before use under the flow of inert gas, whichtypically took 30 minutes. The monomers were purged with inert gas forat least 30 seconds before returning to −20° C.

The indicating silica gel and oxygen absorbing packets from IMPAK werestored in vacuum-sealed foil pouches. After use, any remaining packetswere resealed in fresh pouches. The oxygen absorbers were sealed with acolor changing oxygen indicator tablet. The viability of the materialswas checked before each use by observing the color of the silica gel andthe oxygen indicator tablet.

A 0.15 M phosphate buffer was made by dissolving 9.00 g (0.075 mol)NaH₂PO₄ in 500 mL of distilled water at 25° C. with magnetic stirring.The pH was then adjusted to 7.99 with the dropwise addition of 50%aqueous NaOH. Several other phosphate buffers were prepared in a similarfashion: 0.10 M phosphate at pH 9, 0.10 M phosphate at pH 7.80, 0.10 Mphosphate at 7.72, 0.10 M phosphate at pH 7.46, 0.15 M phosphate at pH7.94, 0.15 M phosphate at pH 7.90, 0.4 M phosphate at pH 9, and 0.05 Mphosphate at pH 7.40.

A sterile 0.10 M phosphate buffer at pH 7.58 with 0.30% HPMC wasprepared for use in kits. First, 1.417 g HPMC was dissolved in 471 mL of0.10 M phosphate buffer at pH 7.58 by vigorous shaking. The viscoussolution was allowed to clarify overnight. The solution was filteredthrough a 0.22 μm filter (Corning #431097) with application of lightvacuum. The viscosity of the resulting solution was measured to be 8.48cSt+/−0.06 at 20° C.

A sterile 0.10 M phosphate buffer at pH 7.58 with 0.3% HPMC wasprepared. First, a 0.10 M phosphate buffer was made by dissolving 5.999g (0.05 mol) of NaH₂PO₄ in 500 mL of distilled water at 20° C. withmagnetic stirring. The pH was then adjusted to 7.58 with the dropwiseaddition of 50% aqueous NaOH. Then, 1.5 g of HPMC was dissolved in 500mL of the above buffer solution by vigorous shaking. The viscoussolution was allowed to clarify overnight. The solution was filteredthrough a 0.22 μm filter (Corning #431097) with application of lightvacuum. The viscosity of the resulting solution was measured via theprocedure as described in the Viscosity Measurements section and wasfound to be 8.48 cSt+/−0.06 at 20° C.

Phosphate buffered saline (PBS) was prepared by dissolving two PBStablets (Sigma Chemical, P4417) in 400 mL of distilled water at 25° C.with vigorous shaking. The solution has the following composition andpH: 0.01 M phosphate, 0.0027 M potassium chloride, 0.137 M sodiumchloride, pH 7.46.

A 0.058 M phosphate buffer was made by dissolving 3.45 g (0.029 mol) ofNaH₂PO₄ in 500 mL of distilled water at 25° C. with magnetic stirring.The pH was then adjusted to 7.97 with the dropwise addition of 50%aqueous NaOH.

A 0.05 M borate buffer was made by dissolving 9.53 g (0.025 mol) ofNa₂B₄O₇.10 H2O in 500 mL of distilled water at 25° C. with magneticstirring. The pH was then adjusted to 7.93 or 8.35 with the dropwiseaddition of 6.0 N HCl.

An antiseptic liquid component was prepared in a similar fashion with acommercial 2% chlorhexidine solution. To 100 mL of 2% chlorhexidinesolution was dissolved 0.3 g of HPMC. The viscous solution was allowedto clarify overnight at 5° C. The resulting clear blue solution has thefollowing composition: 2% chlorhexidine, 0.3% HPMC and an unknownquantity of nontoxic blue dye and detergent.

Other liquid components were prepared in a similar fashion by simplydissolving the appropriate amount of the desired additive to thesolution. For example, an antiseptic liquid component with 1% denatoniumbenzoate, a bittering agent, was prepared by dissolving 2 g ofdenatonium benzoate in 200 mL of 2% chlorhexidine solution.

Alternatively, commercially available drug solutions were used as theliquid component. For example, saline solution, Kenalog-10 (10 mg/mLsolution of triamcinolone acetonide) and Depo-Medrol (40 mg/mL ofmethylprednisolone acetate) were used.

The amine or thiol component (typically in the range of 0.1 mmol armsequivalents) was added to a 50 mL centrifuge tube. A volume of reactionbuffer was added to the tube via a pipette such that the finalconcentration of solids in solution was about 5 percent. The mixture wasgently swirled to dissolve the solids before adding the appropriateamount of ester or epoxide. Immediately after adding the ester orepoxide, the entire solution was shaken for 10 seconds before letting itrest.

The gel time for all cases was measured starting from the addition ofthe ester or epoxide until the gelation of the solution. The gel pointwas noted by pipetting 1 mL of the reaction mixture and observing thedropwise increase in viscosity. Degradation of the polymers wasperformed by the addition of 5 to 10 mL of phosphate buffered saline toca. 5 g of the material in a 50 mL centrifuge tube and incubating themixture at 37° C. The degradation time was measured starting from theday of addition of the phosphate buffer to complete dissolution of thepolymer into solution.

TABLE 1 Components used in formulations. Components Technical NameETTMP-1300 Ethoxylated trimethylolpropane tri(3- mercaptopropionate)4ARM-5k-SH 4ARM PEG Thiol (pentaerythritol) 4ARM-2k-NH2 4ARM PEG Amine(pentaerythritol), HCl Salt, MW 2000 4ARM-5k-NH2 4ARM PEG Amine(pentaerythritol), HCl Salt, MW 5000 8ARM-20k-NH2 8ARM PEG Amine(hexaglycerol), HCl Salt, MW 20000 4ARM-20k-AA 4ARM PEG Acetate AmineHCl Salt, MW 20000 8ARM-20k-AA 8ARM PEG Acetate Amine (hexaglycerol) HClSalt, MW 20000 8ARM-20k-AA 8ARM PEG Acetate Amine (hexaglycerol) TFASalt, MW 20000 4ARM-10k-SG 4ARM PEG Succinimidyl Glutarate(pentaerythritol), MW 10000 8ARM-15k-SG 8ARM PEG Succinimidyl Glutarate(hexaglycerol), MW 15000 4ARM-20k-SGA 4ARM PEG Succinimidyl Glutaramide(pentaerythritol), MW 20000 4ARM-10k-SS 4ARM PEG Succinimidyl Succinate(pentaerythritol), MW 10000 EJ-190 Sorbitol polyglycidyl ether MC MethylCellulose (Methocel ® MC) HPMC Hypromellose(Hydroxypropylmethylcellulose) PVP Povidone (polyvinylpyrrolidone)

Example 1 Manufacture of Hydrogel (Amine-Ester Chemistry)

A solution of 8ARM-20K-NH2 was prepared in a Falcon tube by dissolvingabout 0.13 g solid monomer in about 2.5 mL of sodium phosphate buffer(buffer pH 7.36). The mixture was shaken for about 10 seconds at ambienttemperature until complete dissolution was obtained. The Falcon tube wasallowed to stand at ambient temperature. In another Falcon tube, 0.10 gof 8ARM-15K-SG was dissolved in the same phosphate buffer as above. Themixture was shaken for about 10 seconds and at this point all the powderdissolved. The 8ARM-15K-SG solution was poured immediately into the8ARM-20K-NH2 solution and a timer was started. The mixture was shakenand mixed for about 10 seconds and a 1 mL solution of the mixture waspipetted out using a mechanical high precision pipette. The gel time of1 mL liquid was collected and then verified with the lack of flow forthe remaining liquids. The gel time data of the formulation was recordedand was about 90 seconds.

Example 2 Manufacture of Hydrogel (Amine-Ester Chemistry)

A solution of amines was prepared in a Falcon tube by dissolving about0.4 g solid 4ARM-20k-AA and about 0.2 g solid 8ARM-20k-NH2 in about 18mL of sodium phosphate buffer (buffer pH 7.36). The mixture was shakenfor about 10 seconds at ambient temperature until complete dissolutionwas obtained. The Falcon tube was allowed to stand at ambienttemperature. To this solution, 0.3 g of 8ARM-15K-SG was added. Themixture was shaken to mix for about 10 seconds until all the powderdissolved. 1 mL of the mixture was pipetted out using a mechanical highprecision pipette. The gel time of the formulation was collected usingthe process described above. The gel time was about 90 seconds.

Example 3 Manufacture of Hydrogel (Thiol-Ester Chemistry

A solution of ETTMP-1300 was prepared in a Falcon tube by dissolvingabout 0.04 g monomer in about 5 mL of sodium borate buffer (buffer pH8.35). The mixture was shaken for about 10 seconds at ambienttemperature until complete dissolution was obtained. The Falcon tube wasallowed to stand at ambient temperature. To this solution, 0.20 g of8ARM-15K-SG was added. The mixture was shaken for about 10 seconds untilthe powder dissolved. 1 mL of the mixture was pipetted out using amechanical high precision pipette. The gel time was found to be about 70seconds.

Example 4 Manufacture of Hydrogel (Thiol-Epoxide Chemistry)

A solution of ETTMP-1300 was prepared in a Falcon tube by dissolvingabout 0.04 g monomer in about 5 mL of sodium borate buffer (buffer pH8.35). The mixture was shaken for about 10 seconds at ambienttemperature until complete dissolution was obtained. The Falcon tube wasallowed to stand at ambient temperature. To this solution, 0.10 g ofEJ-190 was added. The mixture was shaken for about 10 seconds untilcomplete dissolution is obtained. 1 mL of the mixture was pipetted outusing a mechanical high precision pipette. The gel time was found to beabout 6 minutes.

Example 5 In Vitro Bioabsorbance Testing

A 0.10 molar buffer solution of pH 7.40 was prepared with deionizedwater. A 50 mL portion of this solution was transferred to a Falcontube. A sample polymer was prepared in a 20 cc syringe. After curing, a2-4 mm thick slice was cut from the polymer slug and was placed in theFalcon tube. A circulating water bath was prepared and maintained at 37°C. The Falcon tube with polymer was placed inside the water bath andtime was started. The dissolution of the polymer was monitored andrecorded. The dissolution time ranged from 1-90 days depending on thetype of sample polymer.

Example 6 Gelling and Degradation Times of Amine-Ester Polymers

Amines studied were 8ARM-20k-NH2 and 4ARM-5k-NH2. The formulationdetails and material properties are given in Table 2. With 8ARM-20k-NH2,it was found that a phosphate buffer with 0.058 M phosphate and pH of7.97 was necessary to obtain acceptable gel times of around 100 seconds.Using a 0.05 M phosphate buffer with a pH of 7.41 resulted in a morethan two-fold increase in gel time (270 seconds).

With the 8ARM-20k-NH2, the ratio of 4ARM-10k-SS to 4ARM-20k-SGA wasvaried from 50:50 to 90:10. The gel time remained consistent, but therewas a marked shift in degradation time around a ratio of 80:20. Forformulations with ratios of 75:25 and 50:50, degradation times spiked toone month and beyond. Using lower amounts of 4ARM-20k-SGA (80:20, 85:15,90:10) resulted in degradation times of less than 7 days.

As a comparison, the 4ARM-5k-NH2 was used in a formulation with a ratioof 4ARM-10k-SS to 4ARM-20k-SGA of 80:20. As was expected, thedegradation time remained consistent, which suggests that the mechanismof degradation was unaffected by the change in amine. However, the geltime increased by 60 seconds, which may reflect the relativeaccessibility of reactive groups in a high molecular weight 8ARM amineand a low molecular weight 4ARM amine.

TABLE 2 Gel and degradation times for varying 4ARM-10k-SS/ 4ARM-20k-SGAratios with 8ARM-15k-SG ester. Ratio of 4ARM-10k- Phosphate SS/4ARM-Reaction Buffer Gel 20k- Concentration Time Degradation Components SGAand pH (s) Time (days) 8ARM-20k-NH2 50/50 0.05M 270 N/A 4ARM-10k-SS, pH7.41 4ARM-20k-SGA 8ARM-20k-NH2 50/50 0.058M 100 >41 4ARM-10k-SS, pH 7.974ARM-20k-SGA 8ARM-20k-NH2 75/25 0.058M 90 29 4ARM-10k-SS, pH 7.974ARM-20k-SGA 8ARM-20k-NH2 80/20 0.058M 100 7 4ARM-10k-SS, pH 7.974ARM-20k-SGA 4ARM-5k-NH2 80/20 0.058M 160 6 4ARM-10k-SS, pH 7.974ARM-20k-SGA 8ARM-20k-NH2 85/15 0.058M 100 5 4ARM-10k-SS, pH 7.974ARM-20k-SGA 8ARM-20k-NH2 90/10 0.058M 90 6 4ARM-10k-SS, pH 7.974ARM-20k-SGA

Example 7 Gelling and Degradation Times of Thiol-Ester Polymers

Thiols studied were 4ARM-5k-SH and ETTMP-1300. The formulation detailsand material properties are given in Table 3. It was found that a 0.05 Mborate buffer with a pH of 7.93 produced gel times of around 120seconds. Increasing the amount of 4ARM-20k-SGA in the formulationincreased the gel time to 190 seconds (25:75 ratio of 4ARM-10k-SS to4ARM-20k-SGA) up to 390 seconds (0:100 ratio of 4ARM-10k-SS to4ARM-20k-SGA). Using a 0.05 M borate buffer with a pH of 8.35 resultedin a gel time of 65 seconds, about a two-fold decrease in gel time.Thus, the gel time may be tailored by simply adjusting the pH of thereaction buffer.

The ratio of 4ARM-10k-SS to 4ARM-20k-SGA was varied from 0:100 to 100:0.In all cases, the degradation time did not vary significantly and wastypically between 3 and 5 days. It is likely that degradation isoccurring via alternate pathways.

TABLE 3 Gel and degradation times for varying 4ARM-10k-SS/4ARM- 20k-SGAratios with 4ARM-5k-SH and ETTMP-1300 thiols. Ratio of Phosphate4ARM-10k- Reaction Buffer Gel Degradation SS/4ARM- Concentration TimeTime Components 20k-SGA and pH (s) (days) 4ARM-5k-SH 50/50 0.05M 65 N/A4ARM-10k-SS, pH 8.35 4ARM-20k-SGA 4ARM-5k-SH 50/50 0.05M 120 44ARM-10k-SS, pH 7.93 4ARM-20k-SGA 4ARM-5k-SH 75/25 0.05M 125 44ARM-10k-SS, pH 7.93 4ARM-20k-SGA 4ARM-5k-SH 90/10 0.05M 115 44ARM-10k-SS, pH 7.93 4ARM-20k-SGA 4ARM-5k-SH 25/75 0.05M 190 44ARM-10k-SS, pH 7.93 4ARM-20k-SGA 4ARM-5k-SH 10/90 0.05M 200 44ARM-10k-SS, pH 7.93 4ARM-20k-SGA ETTMP-1300  0/100 0.05M 390 34ARM-20k-SGA 4ARM-5k-SH 100/0  0.05M 120 4 4ARM-10k-SS pH 7.93

Example 8 Gelling and Degradation Times of Amine-Ester and Thiol-EsterPolymers

An amine (4ARM-5k-NH2) and a thiol (4ARM-5k-SH) were studied with theester 4ARM-10k-SG. The formulation details and material properties aregiven in Table 4. A 0.058 M phosphate buffer with a pH of 7.97 yielded agel time of 150 seconds with the amine. A 0.05 M borate buffer with a pHof 8.35 produced a gel time of 75 seconds with the thiol.

The amine-based polymer appeared to show no signs of degradation, as wasexpected from the lack of degradable groups. However, the thiol-basedpolymer degraded in 5 days. This suggests that degradation is occurringthrough alternate pathways, as was observed in the thiol formulationswith 4ARM-10k-SS and 4ARM-20k-SGA (vida supra).

TABLE 4 Gel and degradation times for amines and thiols with 4ARM-10k-SGformulations. Reaction Buffer Type, Gel Time Degradation ComponentsConcentration, and pH (s) Time (days) 4ARM-5k-NH2 & Phosphate (0.058M,150 Indefinite 4ARM-10k-SG pH 7.97) 4ARM-5k-SH & Borate (0.05M, pH 8.35)75 5 4ARM-10k-SG

Example 9 Gelling and Degradation Times of Thiol-Sorbitol PolyglycidylEther Polymers

With ETTMP-1300 conditions such as high pH (10), high solutionconcentration (50%), or high borate concentration (0.16 M) werenecessary for the mixture to gel. Gel times ranged from around 30minutes to many hours. The conditions that were explored include: pHfrom 7 to 12; solution concentration from 5% to 50%; borateconcentration from 0.05 M to 0.16 M; and thiol to epoxide ratios from1:2 to 2:1.

The high pH necessary for the reaction to occur could result indegradation of the thiol. Thus, a polymer with EJ-190 and 4ARM-5k-SH wasprepared. A 13% solution formulation exhibited a gel time of 230 secondsat a pH of between 9 and 10. The degradation time was 32 days. At alower pH of around 8, the mixture exhibited gel times in the range of 1to 2 hours.

Example 10 General Procedure for the Preparation of PolymerizablePre-Formulations

Several representative sticky formulations are listed in Table 5 alongwith specific reaction details for the preparation of polymerizablepre-formulations. The hydrogel polymers were prepared by firstdissolving the amine component in phosphate buffer or the thiolcomponent in borate buffer. The appropriate amount of the estercomponent was then added and the entire solution was mixed vigorouslyfor 10 to 20 seconds. The gel time was measured starting from theaddition of the ester until the gelation of the solution.

TABLE 5 (A) Summary of the reaction details for several representativesticky formulations without viscosity enhancer; (B) more detailedtabulation of a selection of the reaction details including moles(degradation times were measured in phosphate buffered saline (PBS) at37° C.). (A) Amine or Thiol/Ester Molar Degradation Components RatioBuffer % Solution Gel Time (s) Time (days) 8ARM-20k-NH2 3 0.15Mphosphate, 3 130 N/A 4ARM-20K-SGA pH 7.99 8ARM-20k-NH2 1/3 0.15Mphosphate, 3 300 N/A 4ARM-20K-SGA pH 7.99 8ARM-20k-NH2 3 0.15Mphosphate, 8 50 N/A 4ARM-10K-SS pH 7.99 8ARM-20k-NH2 1/3 0.15Mphosphate, 8 80 N/A 4ARM-10K-SS pH 7.99 4ARM-20K-AA/ 3 0.15M phosphate,5 210 1 to 3 8ARM-20k-NH2 pH 7.99 (75/25) 4ARM-20K-SGA 4ARM-20K-AA/ 50.15M phosphate, 10 180 1 to 3 8ARM-20k-NH2 pH 7.99 (75/25) 4ARM-20K-SGA4ARM-5K-NH2 5 0.10M phosphate, 10 160  7 4ARM-10K-SG pH 7.80 4ARM-5K-NH25 0.10M phosphate, 20 160 1 to 3 4ARM-10K-SS pH 7.80 4ARM-5K-NH2 3 0.10Mphosphate, 5 160 13 4ARM-10K-SG pH 7.80 4ARM-5K-NH2 5 0.15M phosphate,20 80  7 4ARM-10K-SG pH 7.99 4ARM-5K-NH2 5 0.15M phosphate, 30 70 104ARM-10K-SG pH 7.99 4ARM-5K-NH2 5 0.15M phosphate, 19 60 53 4ARM-20K-SGApH 7.99 4ARM-5K-NH2 5 0.15M phosphate, 12 70 53 4ARM-20K-SGA pH 7.994ARM-5K-NH2 1/5 0.15M phosphate, 19 160 15 4ARM-10K-SG pH 7.994ARM-SH-5K 5 0.05M borate, 20 120 2 to 4 4ARM-10K-SG pH 7.93 4ARM-NH2-2K5 0.10M phosphate, 10 120 15 8ARM-15K-SG pH 7.46 4ARM-NH2-2K 7 0.10Mphosphate, 30 150 N/A 4ARM-20K-SGA pH 7.80 (B) Polymer % Wt ArmsSolution Components MW Mmoles (g) Arm mmoles Eq (w/v) 8ARM-20k-NH2 200001000 0.075 8 0.00375 0.03 4ARM-20k-SGA 20000 1000 0.05 4 0.0025 0.01Buffer Volume (phosphate) 4.1 3.0 8ARM-20k-NH2 20000 1000 0.025 80.00125 0.01 4ARM-20k-SGA 20000 1000 0.15 4 0.0075 0.03 Buffer Volume(phosphate) 5.8 3.0 8ARM-20k-NH2 20000 1000 0.3 8 0.015 0.12 4ARM-10k-SS10000 1000 0.1 4 0.01 0.04 Buffer Volume (phosphate) 5 8.0 8ARM-20k-NH220000 1000 0.1 8 0.005 0.04 4ARM-10k-SS 10000 1000 0.3 4 0.03 0.12Buffer Volume (phosphate) 5 8.0

TABLE 6 Gel times for the 8ARM-20k-NH2/4ARM-20k-SGA(1/1) sticky polymersincluding HPMC as viscosity enhancer with varying buffers andconcentrations. Amine/Ester Gel Components Molar Ratio Buffer % SolutionTime (min) 8ARM-20k-NH2 1 0.10M 4.8 1.5 4ARM-20K-SGA phosphate, 0.3%HPMC pH 7.80 8ARM-20k-NH2 1 0.10M 4.8 3.5 4ARM-20K-SGA phosphate, 0.3%HPMC pH 7.46 8ARM-20k-NH2 1 0.05M 4.8 4.5 4ARM-20K-SGA phosphate, 0.3%HPMC pH 7.42 8ARM-20k-NH2 1 0.05M 4 5.5 4ARM-20K-SGA phosphate, 0.3%HPMC pH 7.42 8ARM-20k-NH2 1 0.05M 3 8.5 4ARM-20K-SGA phosphate, 0.3%HPMC pH 7.42 8ARM-20k-NH2 1 0.05M 4.8 6.75 4ARM-20K-SGA phosphate, 0.3%HPMC pH 7.24 8ARM-20k-NH2 1 0.05M 3 12 4ARM-20K-SGA phosphate, 0.3% HPMCpH 7.24 8ARM-20k-NH2 1 0.05M 2.5 15.5 4ARM-20K-SGA phosphate, 0.3% HPMCpH 7.24

Gel times ranged from 60 to 300 seconds and were found to be easilytuned by adjusting the reaction buffer pH, buffer concentration, orpolymer concentration. An example of gel time control for a singleformulation is shown in Table 6, where the gel time for the8ARM-20k-NH2/4ARM-20k-SGA (1/1) polymer was varied from 1.5 to 15.5minutes.

In some instances, the stickiness of the polymers originates from amismatching in the molar equivalents of the components. A variety ofsticky materials using combinations of 4 or 8 armed amines of molecularweights between 2 and 20 thousand and 4 or 8 armed esters of molecularweights between 10 and 20 thousand were created. It was found that incomparison with the 8 armed esters, the 4 armed esters resulted instickier materials. For the amine component, it was found that smallermolecular weights led to stickier materials and higher amine to estermolar ratios.

A mismatch (amine to ester molar ratio) of at least 3 was required toqualitatively sense stickiness. More preferably, a ratio of around 5produced a desirable level of stickiness combined with polymer strength.Polymers with amine to ester molar ratios higher than 5 may be formed aswell, but some reaction conditions, such as the polymer concentration,may need to be adjusted to obtain a reasonable gel time. Furthermore, itwas found that the use of a viscosity enhanced solution improves thepolymers by increasing their strength and elasticity, allowing forhigher amine to ester molar ratios (Example 11; Table 9).

The materials formed were typically transparent and elastic. Stickinesswas tested for qualitatively by touch. Thus, a sticky material adheredto a human finger or other surface and remained in place until removed.Degradation times varied from 1 to 53 days. In certain instances, thepolymer properties, such as gel and degradation times, pore sizes,swelling, etc. may be optimized for different applications withoutlosing the stickiness.

Example 11 General Procedure for the Preparation of Solutions withEnhanced Viscosity

Polymer solutions with enhanced viscosities were prepared by theaddition of a viscosity enhancing agent to the reaction buffer. Table9Blists the viscosity enhancing agents studied, including observations onthe properties of the formed polymers. Stock solutions of reactionbuffers were prepared with varying concentrations of methylcellulose(MC), hypromellose (HPMC) or polyvinylpyrrolidone (PVP). As an example,a 2% (w/w) HPMC solution in buffer was made by adding 0.2 g of HPMC to9.8 mL of 0.10 M phosphate buffer at pH 7.80, followed by vigorousshaking. The solution was allowed to stand overnight. Buffer solutionswith HPMC concentrations ranging from 0.01% to 2.0% were prepared in asimilar fashion. Buffer solutions with PVP concentrations ranging from5% to 20% and buffer solutions with MC concentrations ranging from 1.0to 2.0% were also prepared by a similar method.

The polymers were formed in the same method as described above in thegeneral procedures for the preparation of the sticky materials (Example10). A typical procedure involved first dissolving the amine componentin the phosphate buffer containing the desired concentration ofviscosity enhancing agent. The appropriate amount of the ester componentwas then added and the entire solution was mixed vigorously for 10 to 20seconds. The gel time was measured starting from the addition of theester until the gelation of the solution.

Several representative formulations are listed in Table 7 and Table 8along with specific reaction details. The percent of degradable acetateamine component by mole equivalents is represented by a ratio designatedin parenthesis. For example, a formulation with 75% degradable aminewill be written as 8ARM-20k-AA/8ARM-20k-NH2 (75/25). The polymer wasprepared by first dissolving the amine component in phosphate buffer.The appropriate amount of the ester component was then added and theentire solution was mixed vigorously for 10 to 20 seconds. The gel timewas measured starting from the addition of the ester until the gelationof the solution.

The gel time is dependent on several factors: pH, buffer concentration,polymer concentration, temperature and the monomers used. Previousexperiments have shown that the extent of mixing has little effect onthe gel time once the components are in solution, which typically takesup to 10 seconds. The effect of monomer addition on buffer pH wasmeasured. For the 8ARM-20k-NH2 & 4ARM-20k-SGA formulation, the buffer pHdrops slightly from 7.42 to 7.36 upon addition of the monomers. For the8ARM-20k-AA/8ARM-20k-NH2 (70/30) & 4ARM-20k-SGA formulation, the bufferpH drops from 7.4 to 7.29 upon addition of the monomers. The additionaldecrease in the pH was found to originate from acidic residues in thedegradable acetate amine. The same pH drop phenomenon was observed forthe 4ARM-20k-AA amine. In certain instances, a quality controlspecification on the acetate amine solution pH may be required toimprove the consistency of degradable formulations.

The effect of reaction buffer pH on gel times was determined. The geltimes increase with an increase in the concentration of hydronium ionsin an approximately linear fashion. More generally, the gel timesdecrease with an increase in the buffer pH. In addition, the effect ofreaction buffer phosphate concentration on gel times was investigated.The gel times decrease with an increase in the phosphate concentration.The effect of polymer concentration on gel times was reviewed. The geltimes decrease significantly with an increase in the polymerconcentration. At low polymer concentrations where the gel time isgreater than 5 minutes, hydrolysis reactions of the ester begin tocompete with the formation of the polymer. The effect of temperature ongel times appears to follow the Arrhenius equation. The gel time isdirectly related to the extent of reaction of the polymer solution andso this behavior is not unusual.

The rheology of the polymers during the gelation process was measured asa function of the percent time to the gel point. When 100% representsthe gel point and 50% represents half the time before the gel point, theviscosity of the reacting solution remains relatively constant untilabout 80% of the gel point. After that point, the viscosity increasesdramatically, representing the formation of the solid gel.

The gel time stability of a single formulation using the same lot ofmonomers over the course of about a year was investigated. The monomerswere handled according to the standard protocol outlined above. The geltimes remained relatively stable; some variations in the reaction buffermay account for differences in the gel times.

The gel times for the polymer in the single syringe system used withvarious liquids was reviewed. The gel times remained consistent with theuse of distilled water, Nolvasan, Kenalog-10 and Depo-Medrol. The largeincrease in gel time with the use of saline may be attributed to thepreservatives and buffer in the saline, which was formulated for use asa nasal spray. Pure medical saline for use in IV or irrigation isexpected to yield gel times in line with the current results.

TABLE 7 (A) Summary of the reaction details for several representativesticky formulations; (B) more detailed tabulation of a selection of thereaction details including moles (degradation times were measured inphosphate buffered saline (PBS) at 37° C.). (A) % Gel DegradationComponents Buffer Solution Time (s) Time (days) 4ARM-20k-AA/8ARM-20k-NH20.10M phosphate, 5 150 21 (60/40) pH 7.80 4ARM-20k-SGA4ARM-20k-AA/8ARM-20k-NH2 0.10M phosphate, 5 150 21 (60/40) pH 7.804ARM-20k-SGA 0.3% HPMC 8ARM-20k-NH2 0.10M phosphate, 4.8 100 N/A4ARM-20k-SGA pH 7.80 0.3% HPMC 8ARM-20k-NH2 0.10M phosphate, 4.8 70 488ARM-15k-SG pH 7.80 0.3% HPMC 4ARM-20k-AA/8ARM-20k-NH2 0.10M phosphate,4.8 110 12 (60/40) pH 7.80 8ARM-15k-SG 0.3% HPMC4ARM-20k-AA/8ARM-20k-NH2 0.10M phosphate, 20 160 21 (60/40) pH 7.804ARM-20k-SGA 0.3% HPMC 8ARM-20k-NH2 0.10M phosphate, 4.8 90 N/A4ARM-20k-SGA pH 7.80 8ARM-20k-NH2 0.10M phosphate, 4.8 80 N/A4ARM-20k-SGA pH 7.80 1.0% HPMC 8ARM-20k-NH2 0.10M phosphate, 4.8 210 N/A4ARM-20k-SGA pH 7.46 0.3% HPMC 8ARM-20k-NH2 0.05M phosphate, 4.8 270 N/A4ARM-20k-SGA pH 7.42 0.3% HPMC 8ARM-20k-NH2 0.05M phosphate, 4 330 N/A4ARM-20k-SGA pH 7.42 0.3% HPMC 8ARM-20k-NH2 0.05M phosphate, 3 510 N/A4ARM-20k-SGA pH 7.42 0.3% HPMC 8ARM-20k-NH2 0.05M phosphate, 4.8 405 N/A4ARM-20k-SGA pH 7.24 0.3% HPMC 8ARM-20k-NH2 0.05M phosphate, 3 720 N/A4ARM-20k-SGA pH 7.24 0.3% HPMC 8ARM-20k-NH2 0.05M phosphate, 2.5 930 N/A4ARM-20k-SGA pH 7.24 0.3% HPMC 8ARM-20k-AA 0.10M phosphate, 4.8 90 64ARM-20k-SGA pH 7.46 HPMC (0.3%) 8ARM-20k-AA/8ARM-20k-NH2 0.10Mphosphate, 4.8 100 16 (75/25) pH 7.46 4ARM-20k-SGA HPMC (0.3%)8ARM-20k-AA/8ARM-20k-NH2 0.10M phosphate, 4.8 95 256 (60/40) pH 7.46(estimated) 4ARM-20k-SGA HPMC (0.3%) 8ARM-20k-AA/8ARM-20k-NH2 0.10Mphosphate, 4.8 120 N/A (50/50) pH 7.46 4ARM-20k-SGA HPMC (0.3%)8ARM-20k-AA/8ARM-20k-NH2 0.10M phosphate, 4.8 100 21 (70/30) pH 7.464ARM-20k-SGA HPMC (0.3%) 8ARM-20k-AA/8ARM-20k-NH2 0.10M phosphate, 4.8100 28 (65/35) pH 7.46 4ARM-20k-SGA HPMC (0.3%) 8ARM-20k-NH2 0.10Mphosphate, 4.8 90 N/A 4ARM-20k-SGA 7.80 pH 1.5% HPMC8ARM-20k-AA/8ARM-20k-NH2 0.10M phosphate, 4.8 90 16 (75/25) pH 7.464ARM-20k-SGA HPMC (0.3%) 8ARM-20k-AA/8ARM-20k-NH2 0.10M phosphate, 4.8105 21 (70/30) pH 7.46 4ARM-20k-SGA HPMC (0.3%) 8ARM-20k-AA/8ARM-20k-NH20.10M phosphate, 4.8 120 N/A (50/50) pH 7.46 4ARM-20k-SGA HPMC (0.3%)8ARM-20k-AA/8ARM-20k-NH2 0.10M phosphate, 4.8 70 7 (70/30) pH 7.468ARM-15k-SG HPMC (0.3%) 4ARM-20k-AA/8ARM-20k-NH2 0.10M phosphate, 4.8260 10 (70/30) pH 7.46 4ARM-20k-SGA HPMC (0.3%) 8ARM-20k-AA/8ARM-20k-NH20.10M phosphate, 4.8 70 17 (60/40) pH 7.46 8ARM-15k-SG HPMC (0.3%)8ARM-20k-AA 0.10M phosphate, 4.8 85 7 4ARM-20k-SGA pH 7.46 HPMC (0.3%)8ARM-20k-AA/8ARM-20k-NH2 0.10M phosphate, 4.8 95 13 (70/30) pH 7.464ARM-20k-SGA HPMC (0.3%) 8ARM-20k-AA/8ARM-20k-NH2 0.10M phosphate, 4.895 10 (75/25) pH 7.46 4ARM-20k-SGA HPMC (0.3%) 8ARM-20k-AA/8ARM-20k-NH20.10M phosphate, 4 110 In Progress (75/25) pH 7.58 4ARM-20k-SGA HPMC(0.3%) 8ARM-20k-AA/8ARM-20k-NH2 0.10M phosphate, 3.5 150 In Progress(75/25) pH 7.58 4ARM-20k-SGA HPMC (0.3%) 8ARM-20k-AA/8ARM-20k-NH2 0.10Mphosphate, 3 190 In Progress (75/25) pH 7.58 4ARM-20k-SGA HPMC (0.3%)(B) Polymer Arms % Solution Components MW Mmoles Wt (g) Arm mmoles Eq(w/v) 8ARM-20k-NH2 20000 1000 0.04 8 0.002 0.016 4ARM-20k-SGA 20000 10000.08 4 0.004 0.016 Buffer Volume (phosphate) 2.5 4.8 Viscosity Enhancer0.3% HPMC 8ARM-20k-NH2 20000 1000 0.08 8 0.004 0.032 8ARM-15k-SG 150001000 0.06 8 0.004 0.032 Buffer Volume (phosphate) 2.9 4.8 ViscosityEnhancer 0.3% HPMC 8ARM-20k-AA 20000 1000 0.04 8 0.002 0.0164ARM-20k-SGA 20000 1000 0.08 4 0.004 0.016 Buffer Volume (phosphate) 2.54.8 Viscosity Enhancer 0.3% HPMC 4ARM-20k-AA 20000 1000 0.06 4 0.0030.012 8ARM-20k-NH2 20000 1000 0.02 8 0.001 0.008 4ARM-20k-SGA 20000 10000.1 4 0.005 0.02 Buffer Volume (phosphate) 3.6 5.0 Viscosity Enhancer0.3% HPMC 4ARM-20k-AA 20000 1000 0.12 4 0.006 0.024 8ARM-20k-NH2 200001000 0.04 8 0.002 0.016 8ARM-15k-SG 15000 1000 0.075 4 0.005 0.02 BufferVolume (phosphate) 4.9 4.8 Viscosity Enhancer 0.3% HPMC 8ARM-20k-AA20000 1000 0.06 8 0.003 0.024 8ARM-20k-NH2 20000 1000 0.02 8 0.001 0.0084ARM-20k-SGA 20000 1000 0.16 4 0.008 0.032 Buffer Volume (phosphate) 54.8 Viscosity Enhancer 0.3% HPMC 8ARM-20k-AA 20000 1000 0.03 8 0.00150.012 8ARM-20k-NH2 20000 1000 0.02 8 0.001 0.008 4ARM-20k-SGA 20000 10000.1 4 0.005 0.02 Buffer Volume (phosphate) 3.1 4.8 Viscosity Enhancer0.3% HPMC 8ARM-20k-AA 20000 1000 0.02 8 0.001 0.008 8ARM-20k-NH2 200001000 0.02 8 0.001 0.008 4ARM-20k-SGA 20000 1000 0.08 4 0.004 0.016Buffer Volume (phosphate) 2.5 4.8 Viscosity Enhancer 0.3% HPMC8ARM-20k-AA 20000 1000 0.035 8 0.00175 0.014 8ARM-20k-NH2 20000 10000.015 8 0.00075 0.006 4ARM-20k-SGA 20000 1000 0.1 4 0.005 0.02 BufferVolume (phosphate) 3.1 4.8 Viscosity Enhancer 0.3% HPMC 8ARM-20k-AA20000 1000 0.039 8 0.00195 0.0156 8ARM-20k-NH2 20000 1000 0.021 80.00105 0.0084 4ARM-20k-SGA 20000 1000 0.12 4 0.006 0.024 Buffer Volume(phosphate) 3.75 4.8 Viscosity Enhancer 0.3% HPMC 8ARM-20k-AA 20000 10000.09 8 0.0045 0.036 8ARM-20k-NH2 20000 1000 0.03 8 0.0015 0.0124ARM-20k-SGA 20000 1000 0.24 4 0.012 0.048 Buffer Volume (phosphate) 94.0 Viscosity Enhancer 0.3% HPMC 8ARM-20k-AA 20000 1000 0.075 8 0.003750.03 8ARM-20k-NH2 20000 1000 0.025 8 0.00125 0.01 4ARM-20k-SGA 200001000 0.2 4 0.01 0.04 Buffer Volume (phosphate) 8.55 3.5 ViscosityEnhancer 0.3% HPMC 8ARM-20k-AA 20000 1000 0.06 8 0.003 0.0248ARM-20k-NH2 20000 1000 0.02 8 0.001 0.008 4ARM-20k-SGA 20000 1000 0.164 0.008 0.032 Buffer Volume (phosphate) 8 3.0 Viscosity Enhancer 0.3%HPMC

TABLE 8 (A) Summary of the reaction details for several representativesticky formulations; (B) more detailed tabulation of a selection of thereaction details including moles (degradation times were measured inphosphate buffered saline (PBS) at 37° C.). (A) Appr. Components (ArmPoly. Estim. Deg. Gel Equiv. Mol %) Conc. Buffer Type & Components TimeTime 4ARM-20k-SGA 100% 5% Liquid 0.10M 2 to 4 weeks 125 s 8ARM-20k-AA 65% 2.5 mL Phosphate, 8ARM-20k-NH2  35% pH 7.58 HPMC  0.3% 4ARM-20k-SGA 100% 5% Liquid 0.10M 2 weeks 115 s 8-ARM-20k-AA  75% 2.5 mLPhosphate, 8ARM-20k-NH2  25% pH 7.58 HPMC  0.3%  4ARM-20k-SGA 100% 5%Liquid 0.10M 2 weeks 155 s 8ARM-20k-AA  70% 2.5 mL Phosphate,8ARM-20k-NH2  30% pH 7.58 HPMC  0.3%  4ARM-20k-SGA 100% 5% Liquid 0.10M2 weeks 110 s 8ARM-20k-AA  75% 2.5 mL Phosphate, to 8ARM-20k-NH2  25% pH7.58 125 s HPMC  0.3%  4ARM-20k-SGA 100% 5% Liquid 0.10M 2 weeks 122 s8ARM-20k-AA  75% 2.5 mL Phosphate, 8ARM-20k-NH2  25% pH 7.58 HPMC  0.3% 4ARM-20k-SGA 100% 5% Liquid 0.10M 2 weeks  90 s 8ARM-20k-AA  75% 2.5 mLPhosphate, to 8ARM-20k-NH2  25% pH 7.58 120 s HPMC  0.3%  1000 ppmDenatonium  benzoate 4ARM-20k-SGA 100% 5% Liquid 0.10M 2 weeks  90 s8ARM-20k-AA  75% 2.5 mL Phosphate, to 8ARM-20k-NH2  25% pH 7.58 120sHPMC  0.3%  500 ppm Denatonium benzoate 4ARM-20k-SGA 100% 5% Liquid0.10M 2 weeks  90 s 8ARM-20k-AA  75% 2.5 mL Phosphate, to 8ARM-20k-NH2 25% pH 7.58 120s HPMC  0.3%  100 ppm Denatonium benzoate 4ARM-20k-SGA100% 5% Liquid 0.10M 2 weeks 130 s 8ARM-20k-AA  70% 2.5 mL Phosphate,8ARM-20k-NH2  30% pH 7.58 HPMC  0.3%  4ARM-20k-SGA 100% 4% Liquid 0.10M2 weeks 205 s 8ARM-20k-AA  60% 2.25 mL  Phosphate, to 8-ARM-20k-NH2  40%pH 7.46 230 s HPMC  0.3%  4ARM-20k-SGA 100% 6% Solid 0.10M 30-60 days 90 s 8ARM-20k-AA  65% Freeze-dried (Aldrich) Phosphate, 8ARM-20k-NH2 35% Suggested use w/2 mL pH 7.4  drug solution 4ARM-20k-SGA 100% 5%Liquid 0.10M 2 weeks  90 s 8ARM-20k-AA  75% 2.5 mL Phosphate, to8ARM-20k-NH2  25% pH 7.58 120 s HPMC  0.3%  10000 ppm Denatoniumbenzoate 4ARM-20k-SGA 100% 5% Liquid 0.10M 2 weeks 115 s 8ARM-20k-AA 75% 2.5 mL Phosphate, 8ARM-20k-NH2  25% pH 7.58 HPMC  0.3% 4ARM-20k-SGA 100% 5% Liquid 0.10M 2 weeks 150 s 8ARM-20k-AA  75% 2.5 mLPhosphate, 8ARM-20k-NH2  25% Using freeze-dried pH 7.4  phosphate 1%Denatonium benzoate, 2% Chlorhexidine 4ARM-20k-SGA 100% 6% Solid 0.10M 2weeks 110 s 8ARM-20k-AA  75% Freeze-dried (Aldrich) Phosphate,8ARM-20k-NH2  25% Suggested use w/2 mL pH 7.4  drug solution4ARM-20k-SGA 100% 6% Liquid 0.01M 2 weeks 27 min 8ARM-20k-AA  70% 2.0 mLPhosphate, to 8ARM-20k-NH2  30% Phosphate Buffered 0.137M  31 min HPMC 0.3%  Saline (PBS) NaCl, 0.0027M  KCl, pH 7.2 4ARM-20k-SGA 100% 5%Liquid 0.10M 2 weeks 158 s 8ARM-20k-AA  70% 2.5 mL Phosphate,8ARM-20k-NH2  30% Nolvasan (2% pH 7.4 Chlorhexidine) (B) Polymer % WtArms Solution Components MW Mmoles (g) Arm mmoles Eq (w/v) 8ARM-20k-AA20000 1000 0.03 8 0.0015 0.012 8ARM-20k-NH2 20000 1000 0.01 8 0.00050.004 4ARM-20k-SGA 20000 1000 0.08 4 0.004 0.016 Buffer Volume(phosphate) 2.5 4.8 Viscosity Enhancer 0.3% HPMC 8ARM-20k-AA 20000 10000.03 8 0.0015 0.012 8ARM-20k-NH2 20000 1000 0.01 8 0.0005 0.0044ARM-20k-SGA 20000 1000 0.08 4 0.004 0.016 Buffer Volume (phosphate) 2.54.8 Denatonium benzoate 1000 ppm Viscosity Enhancer 0.3% HPMC8ARM-20k-AA 20000 1000 0.03 8 0.0015 0.012 8ARM-20k-NH2 20000 1000 0.018 0.0005 0.004 4ARM-20k-SGA 20000 1000 0.08 4 0.004 0.016 Buffer Volume(phosphate) 2.5 4.8 Denatonium benzoate  500 ppm Viscosity Enhancer 0.3%HPMC 8ARM-20k-AA 20000 1000 0.03 8 0.0015 0.012 8ARM-20k-NH2 20000 10000.01 8 0.0005 0.004 4ARM-20k-SGA 20000 1000 0.08 4 0.004 0.016 BufferVolume (phosphate) 2.5 4.8 Denatonium benzoate  100 ppm ViscosityEnhancer 0.3% HPMC 8ARM-20k-AA 20000 1000 0.03 8 0.0015 0.0128ARM-20k-NH2 20000 1000 0.01 8 0.0005 0.004 4ARM-20k-SGA 20000 1000 0.084 0.004 0.016 Buffer Volume (phosphate) 2.5 4.8 Denatonium benzoate10000 ppm  Viscosity Enhancer 0.3% HPMC 8ARM-20k-AA 20000 1000 0.03 80.0015 0.012 8ARM-20k-NH2 20000 1000 0.01 8 0.0005 0.004 4ARM-20k-SGA20000 1000 0.08 4 0.004 0.016 Solid Phosphate 0.043 Nolvasan Volume (2%chlorhexidine) 2.5 4.8 Denatonium benzoate 10000 ppm  8ARM-20k-AA 200001000 0.026 8 0.0013 0.0104 8ARM-20k-NH2 20000 1000 0.014 8 0.0007 0.00564ARM-20k-SGA 20000 1000 0.08 4 0.004 0.016 Buffer Volume (phosphate) 2.54.8 Viscosity Enhancer 0.3% HPMC 8ARM-20k-AA 20000 1000 0.028 8 0.00140.0112 8ARM-20k-NH2 20000 1000 0.012 8 0.0006 0.0048 4ARM-20k-SGA 200001000 0.08 4 0.004 0.016 Buffer Volume (phosphate) 2.5 4.8 ViscosityEnhancer 0.3% HPMC 8ARM-20k-AA 20000 1000 0.018 8 0.0009 0.00728ARM-20k-NH2 20000 1000 0.012 8 0.0006 0.0048 4ARM-20k-SGA 20000 10000.06 4 0.003 0.012 Buffer Volume (phosphate) 2.25 4 Viscosity Enhancer0.3% HPMC 8ARM-20k-AA 20000 1000 0.026 8 0.0013 0.0104 8ARM-20k-NH220000 1000 0.014 8 0.0007 0.0056 4ARM-20k-SGA 20000 1000 0.08 4 0.0040.016 Solid Phosphate 0.035 6 Drug Solution 2.0 mL 8ARM-20k-AA 200001000 0.027 8 0.00135 0.0108 8ARM-20k-NH2 20000 1000 0.009 8 0.000450.0036 4ARM-20k-SGA 20000 1000 0.072 4 0.0036 0.0144 Solid Phosphate0.035 5.4 Drug Solution 2.0 mL 8ARM-20k-AA 20000 1000 0.028 8 0.00140.0112 8ARM-20k-NH2 20000 1000 0.012 8 0.0006 0.0048 4ARM-20k-SGA 200001000 0.08 4 0.004 0.016 Buffer Volume (phosphate) 2 6 Viscosity Enhancer0.3% HPMC 8ARM-20k-AA 20000 1000 0.028 8 0.0014 0.0112 8ARM-20k-NH220000 1000 0.012 8 0.0006 0.0048 4ARM-20k-SGA 20000 1000 0.08 4 0.0040.016 Solid Phosphate 0.043 Nolvasan Volume (2% chlorhexidine) 2.5 4.8Denatonium benzoate 1%

Cytotoxicity & Hemolysis Evaluation

Several polymer samples were sent out to NAMSA for cytotoxicity andhemolysis evaluation. Cytotoxic effects were evaluated according to ISO10993-5 guidelines. Hemolysis was evaluated according to proceduresbased on ASTM F756 and ISO 10993-4.

The polymer 8ARM-20k-NH2 & 4ARM-20k-SGA at 4.8% solution with 0.3% HPMCwas found to be non-cytotoxic and non-hemolytic. The polymer8ARM-20k-AA/8ARM-20k-NH2 (70/30) & 4ARM-20k-SGA at 4.8% solution with0.3% HPMC was found to be non-cytotoxic and non-hemolytic. In addition,formulations involving 4ARM-20kAA and 8ARM-15k-SG were alsonon-cytotoxic and non-hemolytic.

Gel and Degradation Time Measurements

The gel time for all cases was measured starting from the addition ofthe ester until the gelation of the solution. The gel point was noted bypipetting 1 mL of the reaction mixture and observing the dropwiseincrease in viscosity until the mixture ceased to flow. Degradation ofthe polymers was performed by the addition of 1 to 10 mL of phosphatebuffered saline per 1 g of the material in a 50 mL centrifuge tube andincubating the mixture at 37° C. A digital water bath was used tomaintain the temperature. The degradation time was measured startingfrom the day of addition of the phosphate buffer to complete dissolutionof the polymer into solution.

The effect of reaction buffer pH, phosphate concentration, polymerconcentration and reaction temperature on the gel times werecharacterized. The buffer pH was varied from 7.2 to 8.0 by the dropwiseaddition of either 50% aqueous NaOH or 6.0 N HCl. Phosphateconcentrations of 0.01, 0.02 and 0.05 M were prepared and adjusted to pH7.4. Polymer concentrations from 2 to 20% solution were studied.Reaction temperatures of 5, 20, and 37° C. were tested by keeping themonomers, buffers, and reaction mixture at the appropriate temperature.The 5° C. environment was provided by a refrigerator and the 37° C.temperature was maintained via the water bath. Room temperature wasfound to be 20° C.

The effect of degradation buffer pH and the proportion of degradableamine in the polymer formulation on the degradation times were explored.The degradation buffer pH was varied from 7.2 to 9.0 by the dropwiseaddition of either 50% aqueous NaOH or 6.0 N HCl. The degradable aminecomponents studied were either the 4ARM-20k-AA or the 8ARM-20k-AA, andthe percent of degradable amine relative to the non-degradable amine wasvaried from 50 to 100%.

The degradation time is largely dependent on the buffer pH, temperature,and the monomers used. Degradation occurs primarily through ester bondhydrolysis; in biological systems, enzymatic pathways may also play arole. FIG. 1 compares the degradation times of formulations with4ARM-20k-AA and 8ARM-20k-AA in varying amounts. In general, increasingthe amount of degradable acetate amine in relation to the non-degradableamine decreases the degradation times. Additionally, in some instances,the 8ARM-20k-AA exhibits a longer degradation time than the 4ARM-20k-AAper mole equivalent, which becomes especially apparent when the percentof acetate amine drops below 70%.

The effect of the buffer pH on the degradation time was measured. The pHrange between 7.2 and 9.0 was studied. In general, a high pH environmentresults in a greatly accelerated degradation. For example, an increasein pH from approximately 7.4 to 7.7 decreases the degradation time byabout half.

The degradation time of different Acetate Amine formulations wasinvestigated. A pre-formulation with 70% Acetate Amine has a degradationtime of approximately 14 days whereas a pre-formulation with 62.5%Acetate Amine has a degradation time of approximately 180 days.

FIG. 2 shows the effect of polymer concentration on degradation time fordifferent Acetate Amine formulations, where increasing polymerconcentration slightly increases the degradation time (75% Acetate Amineformulation). This effect is less apparent for 100% Acetate Amineformulation, where the rate of ester hydrolysis is more significant.

The monomers used in the formulations have also been found to play arole in the way the polymer degrades. For the 8ARM-20k-AA/8ARM-20k-NH2(70/30) & 4ARM-20k-SGA polymer, degradation occurred homogeneouslythroughout the material, resulting in a “smooth” degradation process.Thepolymer absorbed water and swelled slightly over the initial fewdays. Then, the polymer became gradually softer yet maintained itsshape. Finally, the polymer lost its shape and became a highly viscousfluid.

When the amount of degradable amine becomes low, non-degradable regionsin the polymer may occur. The 8ARM-20k-AA/8ARM-20k-NH2 (60/40) &4ARM-20k-SGA formulation after approximately 80 days was compared withthe 4ARM-20k-AA/8ARM-20k-NH2 (70/30) & 4ARM-20k-SGA formulation. The4ARM-20k-AA/8ARM-20k-NH2 (70/30) & 4ARM-20k-SGA formulation degradedinto several large fragments. For applications where the polymers aresubjected to great forces, fragmentation may also occur as the polymerbecomes softer and weaker over time.

Polymer Concentration

More dilute polymer solutions may be employed with minimal changes inthe mechanical properties. For the formulation8ARM-20k-AA-20K/8ARM-20k-NH2 (75/25) with 4ARM-20k-SGA and 0.3% HPMC,polymer concentrations of 3.0, 3.5 and 4.0% were studied. FIG. 3A showsthe gel times, which increased steadily as the polymer concentration waslowered. The firmness decreased slightly as the polymer concentrationwas lowered (FIG. 3B). The tack is shown in FIG. 3C. There wasessentially no change in the polymer adhesive properties. The elasticmodulus decreased slightly as the polymer concentration was lowered(FIG. 3D).

TABLE 9 (A) Reaction details for specific sticky formulation; (B)formulation results for a specific sticky formulation with a variety ofviscosity enhancing agents (the hydrogel surface spread test isconducted on a hydrophilic hydrogel surface composed of 97.5% water atan angle of approximately 30°; one drop of the polymer solution from a22 gauge needle is applied to the surface before gelation); (C) theclarity of solutions containing a variety of viscosity enhancing agents,as measured by the % transmission at 650 nm. (A) Components MW wt (g)Arm mmoles Arms Eq % Solution 8ARM-20k-NH2 20000 0.04 8 0.002 0.0164ARM-20k-SGA 20000 0.08 4 0.004 0.016 Phosphate buffer 2.5 mL 0.10M, pH7.80 4.8 (B) Viscous Approx. Gel Hydrogel Surface Agent Viscosity TimeSpread Test % (w/w) (cP) (s) Category Notes 0 (Original 1.1 80 2 Rigid,has “bounce”. Slight elasticity. Formulation)  5% PVP 1 to 5 90 2 to 3No change, except for a slight increase in elasticity. 10% PVP 3 to 5 902 to 3 Slightly opaque, moderate increase in elasticity. Slippery. 15%PVP  5 to 10 100 2 to 3 Opaque, definite increase in elasticity.Slippery when wet, slightly sticky when dry. 20% PVP 10 110 2 Opaque,definite increase in elasticity. Slippery when wet, very sticky whendry.  0.3% HPMC 8.4 80 2 No change.  1.0% HPMC 340.6 90 1 No change.1.25% HPMC 1,000 90 1 No change.  1.5% HPMC 2,000 100 1 Slightly softer,lacks “bounce”.  2.0% HPMC 4,000 100 1 Slightly softer, lacks “bounce”.Slippery. (C) Sample % Transmission @ 650 nm 0.10M phosphate buffer, pH7.80 100.0%  10% PVP 99.9% 1.5% HPMC 95.7% 1.0% HPMC 96.8% 0.5% HPMC99.1% 0.1% HPMC 99.6% Hydrogel Surface Spread Test Categories: 1) Nospreading, tight drops that stay in place; 2) Mild spreading, drops dripslowly down; 3) Severe spreading, drops completely wet surface. Water isin category 3.

Methylcellulose (MC) was found to behave similarly to hypromellose(HPMC) and provided workable viscous solutions in the concentrationrange of 0 to 2% (w/w). However, the HPMC dissolved more readily thanthe MC, and the HPMC solutions possessed greater optical clarity; thusthe use of HPMC was favored. Povidone (PVP) dissolved easily in thebuffer, but provided minimal viscosity enhancement even at 20% (w/w).Higher molecular weight grades of PVP are available, but have not yetbeen explored.

For the most part, the polymers remain unchanged by the addition of lowconcentrations of HPMC or PVP. However, there was a noticeable change inthe polymer around 0.3% HPMC that was characterized by an enhancedelasticity, as evidenced by the ability of the material to elongate morethan usual without breakage. Above 1.5% HPMC, the polymer becameslightly softer and exhibited less bounce. The gel times also remainedwithin 10 seconds of the gel time for the formulation with no viscousagent. In the case of PVP, significant changes in the polymer occurredabove 10% PVP. The polymer became more opaque with a noticeable increasein elasticity and stickiness. At 15% to 20% PVP, the polymer becamesimilar to the sticky materials, but with a better mechanical strength.The gel times also increased by roughly 20 seconds relative to theformulation with no viscous agent. Thus, the addition of lowerconcentrations of PVP or HPMC to the polymer solutions may be beneficialin improving the polymer's elasticity and lubricity.

The results of the hydrogel surface spread test show that mostformulations belong in category 2.

Based on the these observations, a formulation utilizing 0.3% HPMC waschosen for further evaluation. Above 1.0% HPMC, the solutions becamesignificantly more difficult to mix and dissolution of the monomersbecame an issue. At 0.5% HPMC and above, the formation of air bubblesduring mixing became significant. Furthermore, the solutions were noteasily filtered through a 0.5 μm syringe filter to remove the bubbles.However, the 0.3% HPMC solution was easily filtered even after moderatemixing, resulting in a bubble-free, optically clear polymer.

Viscosity Measurements

The viscosities of the resulting buffer solutions were measured with theappropriately sized Cannon-Fenske viscometer tube from Ace Glass.Viscometer sizes used ranged from 25 to 300. Measurements of selectsolutions were performed in triplicate at both 20° C. and 37° C. Theresults are shown in Table 9B. To calculate the approximate dynamicviscosities, it was assumed that all the buffer solutions had the samedensity as water.

To characterize the rheology of the polymers during the gelationprocess, a size 300 viscometer was used with a formulation that wasdesigned to gel after approximately 15 minutes. The formulation usedinvolved the 8ARM-20k-NH2 with the 4ARM-20k-SGA ester at 2.5% solutionand 0.3% HPMC. The reaction occurred in a 0.05 M phosphate buffer at apH of 7.2. Thus, one viscosity measurement with the size 300 viscometerwas obtained in about one minute and subsequent measurements may beobtained in quick succession up to the gel point.

Hydrogel Surface Spread Test

To model the performance of the polymer solutions on a hydrophilicsurface the extent of spreading and dripping of droplets on a high watercontent hydrogel surface at an incline of about 30° was recorded. Thehydrogel was made by dissolving 0.10 g (0.04 mol arm eq.) of8ARM-20k-NH2 in 7 mL 0.05 M phosphate buffer at pH 7.4 in a Petri-dish,followed by the addition of 0.075 g (0.04 mol arm eq.) of 8ARM-15k-SGester. The solution was stirred with a spatula for 10 to 20 seconds andallowed to gel, which typically took 5 to 10 minutes. The water contentof the resulting polymer was 97.5%.

The test was performed by first preparing the polymer solution in theusual fashion. After thorough mixing, the polymer solution was dispenseddropwise through a 22 gauge needle onto the hydrogel surface. Theresults are shown in Table 9B and were divided into three generalcategories: 1) no spreading, tight drops that stay in place; 2) mildspreading, drops drip slowly down; 3) severe spreading, drops completelywet surface. Water is in category 3.

Swelling & Drying Measurements

The extent of swelling in the polymers during the degradation processwas quantified as the liquid uptake of the polymers. A known mass of thepolymer was placed in PBS at 37° C. At specified time intervals, thepolymer was isolated from the buffer solution, patted dry with papertowels and weighed. The percent increase in the mass was calculated fromthe initial mass.

The fate of the polymers in air under ambient conditions was quantifiedas the weight loss over time. A polymer film of about 1 cm thickness wasplaced on a surface at 20° C. Mass measurements were performed at setintervals. The percent weight loss was calculated from the initial massvalue.

The percent of water uptake by the 8ARM-20k-NH2/4ARM-20k-SGA polymerswith 0, 0.3 and 1.0% HPMC was measured. The 1.0% HPMC polymer absorbedup to 30% of its weight in water until day 20. After day 20, the polymerreturned to about 10% of its weight in water. In comparison, the 0% HPMCpolymer initially absorbed up to 10% of its weight in water, but beganto lose water gradually, hovering about 5% of its weight in water. The0.3% HPMC polymer behaved in an intermediate fashion. It initiallyabsorbed up to 20% of its weight in water, but returned to about 10% ofits weight in water after a week and continued to slowly lose water.

The percent of weight loss under ambient conditions over 24 hours by the8ARM-20k-AA/8ARM-20k-NH2 (75/25) & 4ARM-20k-SGA polymer with 0.3% HPMCand 1.0% HPMC is shown in FIG. 4. Ambient conditions were roughly 20° C.and 30 to 50% relative humidity. The rate of water loss was fairlyconstant over 6 hours at about 10% per hour. After 6 hours, the rateslowed significantly as the polymer weight approached a constant value.The rate of water loss is expected to vary based on the polymer shapeand thickness, as well as the temperature and humidity.

Specific Gravity Measurements

The specific gravity of the polymers was obtained by preparing thepolymer solution in the usual fashion and pipetting 1.00 mL of thethoroughly mixed solution onto an analytical balance. The measurementswere performed in triplicate at 20° C. The specific gravity wascalculated by using the density of water at 4° C. as the reference.

The specific gravity of the polymers did not differ significantly fromthat of the buffer solution only, both of which were essentially thesame as the specific gravity of water. Exceptions may occur when thepolymer solution is not filtered and air bubbles become embedded in thepolymer matrix.

Barium Sulfate Suspensions

For imaging purposes, barium sulfate was added to several polymerformulations as a radiocontrast agent. Barium sulfate concentrations of1.0, 2.0, 5.0 and 10.0% (w/v) were explored. The viscosity of theresulting polymer solutions was measured and the effect of bariumsulfate addition on the polymer gel times and syringabilitycharacteristics were also studied.

Barium sulfate concentrations of 1.0, 2.0, 5.0 and 10.0% (w/v) wereexplored. The opaque, milky white suspensions formed similarly opaqueand white polymers. No changes in the gel times were observed.Qualitatively, the polymers appeared to have similar properties to thatof polymers without barium sulfate. All formulations were able to bereadily dispensed through a 22 gauge needle.

The viscosity barium sulfate concentrations of 1.0, 2.0, 5.0 and 10.0%remained relatively stable up to 2.0%; at 5.0%, the viscosity increasedslightly to about 2.5 cP. There was a sharp increase in the viscosity tonearly 10 cP as the concentration approached 10.0%. Thus, a bariumsulfate concentration of 5.0% was chosen as a balance between highcontrast strength and similarity to unmodified polymer formulations.

Hydrogel Firmness, Elastic Modulus, and Adhesion

The firmness of the polymers was characterized by a Texture Analyzermodel TA.XT.plus with Exponent software version 6.0.6.0. The methodfollowed the industry standard “Bloom Test” for measuring the firmnessof gelatins. In this test, the TA-8¼″ ball probe was used to penetratethe polymer sample to a defined depth and then return out of the sampleto the original position. The peak force measured is defined as the“firmness” of the sample. For the polymers studied, a test speed of 0.50mm/sec, a penetration depth of 4 mm, and a trigger force of 5.0 g wereused. The polymers were prepared on a 2.5 mL scale directly in a 5 mLsize vial to ensure consistent sample dimensions. The vials used wereThermoScientific/Nalgene LDPE sample vials, product#6250-0005(LOT#7163281060). Measurements were conducted at 20° C. The polymerswere allowed to rest at room temperature for approximately 1 hour beforemeasuring. Measurements were performed in triplicate for at least threesamples. A sample plot generated by the Exponent software running thefirmness test is given in FIG. 5. The peak of the plot represents thepoint at which the target penetration depth of 4 mm was reached.

The elastic modulus of the polymers was characterized by a TextureAnalyzer model TA.XT.plus with Exponent software version 6.0.6.0. Inthis test, the TA-19 Kobe probe was used to compress a polymer cylinderof known dimensions until fracture of the polymer occurs. The probe hasa defined surface area of 1 cm². The modulus was calculated as theinitial slope up to 10% of the maximum compression stress. For thepolymers studied, a test speed of 5.0 mm/min and a trigger force of 5.0g were used. The sample height was auto-detected by the probe. Thepolymers were prepared on a 2.5 mL scale directly in a 5 mL size vialcap to ensure consistent sample dimensions. The vials used wereThermoScientific/Nalgene LDPE sample vials, product#6250-0005(LOT#7163281060). Measurements were conducted at 20° C. The polymerswere allowed to rest at room temperature for approximately 1 hour beforemeasuring. Measurements were performed for at least three samples. Asample plot generated by the Exponent software running the modulus testis given in FIG. 6. The polymers typically behaved elastically for theinitial compression, as evidenced by the nearly linear plot.

The adhesive properties of the polymers were characterized by a TextureAnalyzer model TA.XT.plus with Exponent software version 6.0.6.0. In theadhesive test, the TA-57R 7 mm diameter punch probe was used to contactthe polymer sample with a defined force for a certain amount of time,and then return out of the sample to the original position. An exemplaryplot generated by the Exponent software running the adhesive test isgiven in FIG. 7. The plot begins when the probe hits the surface of thepolymer. The target force is applied on the sample for a defined unit oftime, represented by the constant force region in the plot. Then, theprobe returns out of the sample to the original position and theadhesive force between the probe and the sample is measured as the“tack”, which is the peak force required to remove the probe from thesample. Other properties that were measured include the adhesion energyor the work of adhesion, and the material's “stringiness.” The adhesionenergy is simply the area under the curve representing the tack force.Thus, a sample with a high tack and low adhesion energy willqualitatively feel very sticky, but may be cleanly removed with a quickpull; a sample with a high tack and high adhesion energy will also feelvery sticky, but the removal of the material will be more difficult andmay be accompanied by stretching of the polymer, fibril formation andadhesive residues. The elasticity of the polymer is proportional to themeasured “stringiness”, which is the distance the polymer stretcheswhile adhered to the probe before failure of the adhesive bond. For thepolymers studied, a test speed of 0.50 mm/sec, a trigger force of 2.0 g,and a contact force of 100.0 g and contact time of 10.0 sec were used.The polymers were prepared on a 1.0 to 2.5 mL scale directly in a 5 mLsize vial to ensure consistent sample surfaces. The vials used wereThermoScientific/Nalgene LDPE sample vials. Measurements were conductedat 20° C. The polymers were allowed to rest at room temperature forapproximately 1 hour before measuring. As reference materials, theadhesive properties of a standard Post-It Note® and Scotch Tape® weremeasured. All measurements were performed in triplicate. The averagesand standard deviations were calculated.

The effect of HPMC addition to the mechanical properties of the polymerswas explored, along with the effect of adding degradable 8ARM-20k-AAamine. The results are shown in FIG. 8 and FIG. 9. Under the statedconditions of the firmness test, it was found that the addition of 0.3%HPMC decreased the firmness of the polymer by about half (FIG. 8A). Thiscorresponds to a slight decrease in the elastic modulus (FIG. 9A). The1.0% HPMC polymer had approximately the same firmness as the 0.3% HPMCpolymer, but a slight decrease in the elastic modulus. The disparitybetween the firmness and modulus tests is likely due to experimentalerror. The polymer solutions were not filtered, so the presence of airbubbles likely increased the errors. The water content of the polymersmay also change as the polymers were sitting in the air, essentiallychanging the physical properties of the materials.

It was found that the addition of the degradable 8ARM-20k-AA amine didnot substantially change the measured values of the firmness or theelastic modulus (FIG. 8B and FIG. 9B). The results of the adhesiontesting are shown in FIG. 10. The measured values for a standardcommercial Post-It™ Note are also included as a reference. The polymertack was found to be around 40 mN, which is about three times less thanthat of a Post-It™ Note. The adhesive properties of the polymer were notfound to vary with the addition of the degradable amine.

FIG. 11 shows the firmness vs. degradation time for the8ARM-20k-AA/8ARM-20k-NH2 (70/30) & 4ARM-20k-SGA at 4.8% solution with0.3% HPMC. The error bars represent the standard deviations of 3samples. The degradation time for the polymer was 18 days. The firmnessof the polymer strongly correlated with the extent of degradation.Swelling may also play a role during the early stages.

The effect of various additives to the formulation on the polymerproperties was explored. FIG. 12 shows the gel time, degradation time,firmness, adhesion and elastic modulus for polymers prepared withvarying combinations of 1% HPMC, 2% chlorhexidine and 1% denatoniumbenzoate. Essentially no change in the polymer properties were foundexcept for formulations containing 2% chlorhexidine, which exhibiteddecreased firmness and elastic modulus. It was apparent from visualinspection of the polymer that the change was due to the detergentpresent in the Nolvasan solution used and not the chlorhexidine; thedetergent caused heavy foaming during mixing that gelled into an aeratedpolymer.

FIG. 13 shows the effect of using Kenalog-10 or Depo-Medrol drugsolutions with the single syringe system on the polymer properties. Thedrug loaded polymers are slightly softer and more elastic relative tothe reference, presumably due to the presence of viscosity enhancers inthe drug solutions.

Optical Clarity

A Thermo Scientific GENESYS 10S UV-Vis spectrophotometer was used tomeasure the optical clarity of the viscous solutions. To a quartzcuvette, 1.5 mL of the sample solution was pipetted. The buffer solutionwith no additives was used as the reference. The stable % transmissionof the sample was recorded at 650 nm and the results are listed in Table9C.

To measure the light transmission of the polymers, 1 mL of polymersolution was filtered with a 5 μm filter into a cuvette before gelation.The cuvette was then placed horizontally so that the polymer gelled onthe side of the cuvette as a film. The film thickness was found to be 3mm. The polymer was allowed to cure for 15 minutes at room temperaturebefore measuring the % light transmission at 400, 525 and 650 nm withair as the reference.

All of the viscous solutions under consideration were found to haveacceptable to excellent optical clarity under the concentration rangesused (greater than 97% transmission). For the highly viscous solutions,air bubble formation during mixing was observed, which may be resolvedby the addition of an anti-foaming agent, or through the use of asyringe filter (See Table 9C).

The polymers exhibited excellent optical clarities over the visiblespectrum. The lowest % transmission relative to buffer only was 97.2%and the highest was 99.7%. The drop in the % transmission at lowerwavelengths is likely due to some energy absorption as the ultravioletregion is approached. The results are shown in FIG. 14.

Drug Elution: General Procedures

A Thermo Scientific GENESYS 10S UV-Vis spectrophotometer was used toquantify the release of various drugs from several polymers. First, thereference drug or drug solution was dissolved in an appropriate solvent.Typically, phosphate buffered saline (PBS), ethanol or dimethylsulfoxide(DMSO) were used as the solvent. Next, the optimal absorption peak foridentifying and quantifying the drug was determined by performing a scanof the drug solution between 200 and 1000 nm. With the absorption peakselected, a reference curve was established by measuring the peakabsorbance for various concentrations of the drug. The different drugconcentration solutions were prepared by standard dilution techniquesusing analytical pipettes. A linear fit of the absorbance vs. drugconcentration resulted in a general equation that was used to convertthe measured absorbance of the elution samples to the drugconcentration.

The polymer was prepared with a known drug dosage in the same fashion asa doctor administering the polymer in a clinical setting. However, inthis case the polymer was molded into a cylinder with a diameter ofapproximately 18 mm. The polymer cylinder was then placed in a 50 mLFalcon tube with a set amount of PBS and placed at 37° C. Thetemperature was maintained by a digitally controlled water bath.

Elution samples were collected daily by decanting the PBS solution fromthe polymer. The volume of sample collected was recorded. The polymerwas placed in a volume of fresh PBS equivalent to the volume of samplethat was collected and returned to 37° C. The elution sample wasanalyzed by first diluting the sample in the appropriate solvent usinganalytical pipettes such that the measured absorbance was in the rangedetermined by the reference curve. The dilution factor was recorded. Thedrug concentration was calculated from the measured absorbance via thereference curve and the dilution factor. The drug amount was calculatedby multiplying the drug concentration with the sample volume. Thepercent elution for that day was calculated by dividing the drug amountby the total amount of drug administered.

Drug Elution: Chlorhexidine

The peak found between 255 and 260 nm was chosen and a reference curvewas established by measuring the peak absorbance for 0, 0.5, 1, 2.5, 5,10, 20, 40, and 50 ppm of chlorhexidine. Concentrations above 50 ppm didnot exhibit linear behavior in peak absorbance.

The polymer was prepared with a commercial Nolvasan solution, whichcorresponds to a 2% chlorhexidine dose (50 mg). The elution volume was 2mL of PBS per 1 g of polymer. The elution samples were stored at 20° C.The elution samples were analyzed by diluting the sample 1,000-fold withdimethyl sulfoxide (DMSO) in a quartz cuvette.

The chlorhexidine elution behavior proceeded similarly to previousexperiments with other small molecules. Almost half of the chlorhexidinewas released within the first three days. Then, the elution rate sloweddramatically for the next three to four days followed by another largerelease of chlorhexidine as the polymer degrades (FIG. 15).

Drug Elution Triamcinolone Acetonide (Kenalog)

The peak found between 235 and 245 nm was chosen and a reference curvewas established by measuring the peak absorbance for 0, 0.002, 0.004,0.008, 0.01, 0.04, 0.08 and 0.10 mg per mL of triamcinolone acetonide.Concentrations above 0.10 mg per mL did not exhibit linear behavior inpeak absorbance.

The polymer was prepared with a commercial Kenalog-10 solution, whichcorresponds to a 10 mg per mL dose (20 mg). It should be noted that thecommercial drug solution contained 0.9% of benzyl alcohol, which mayinterfere with the UV measurement at low concentrations oftriamcinolone. However, it is significantly more soluble in PBS than thetriamcinolone and was thus removed by leeching it out from the polymerwith PBS at 37° C. for 2 to 4 hours. The solution was found to containthe majority of the contaminant and negligible amounts of drug by UV-Visand was discarded. The elution volume was varied for different polymersand ranged from 2 mL of PBS per 1 g of polymer to 20 mL of PBS per 1 gof polymer. The elution samples were stored at 20° C. The elutionsamples were analyzed by diluting the sample with ethanol in a quartzcuvette by ½.

Drug Elution Methylprednisolone Acetate (Depo-Medrol)

The peak found between 235 and 245 nm was chosen and a reference curvewas established by measuring the peak absorbance for 0, 0.001, 0.002,0.004, 0.005, 0.008, 0.01, 0.04, 0.05 and 0.08 mg per mL ofmethylprednisolone acetate. Concentrations above 0.08 mg per mL did notexhibit linear behavior in peak absorbance.

The polymer was prepared with a commercial Depo-Medrol solution, whichcorresponds to a 40 mg per mL dose (80 mg). It should be noted that thecommercial drug solution contained 0.0195% of myristyl-gamma-picoliniumchloride, which may interfere with the UV measurement at lowconcentrations of methylprednisolone. However, it is significantly moresoluble in PBS than the methylprednisolone and was thus removed byleeching it out from the polymer with PBS at 37° C. for 2 to 4 hours.The solution was found to contain the majority of the contaminant andnegligible amounts of drug by UV-Vis and was discarded. The elutionvolume was 2 mL of PBS per 1 g of polymer. The elution samples werestored at 20° C. The elution samples were analyzed by diluting thesample with ethanol in a quartz cuvette, typically by ⅕ or 1/10.

The elution of the steroidal drugs, triamcinolone andmethylprednisolone, behaved similarly. The first few days typicallyexhibit an elevated elution rate, presumably as weakly bound surfacedrug is released. Then, the elution is relatively constant at a ratethat is related to the drug solubility. Finally, the remaining drug inthe polymer is released as degradation begins. Several examples aregiven in FIG. 16, FIG. 17, and FIG. 18 of the control over the elutionbehavior that was developed. Drugs may be released over a short time(weeks) or long period (years, projected).

Drug Elution: Kinetic Measurements

Several experiments were performed with Kenalog-10 loaded polymers toobtain a better understanding of the elution behavior. The polymer and aseparate PBS solution were first equilibrated to 37° C. At a specifiedinitial time point, the polymer was added to the PBS solution.Measurements were performed at specific time intervals for up to 3 days.The drug concentrations and amounts over time were plotted and analyzed.

Several preliminary experiments were performed with Kenalog-10 loadedpolymers to obtain a better understanding of the elution behavior. Insummary, 0th order release kinetics was observed, presumably due to thelow solubility of the drug. The measured rate constant was 2.90±0.08 μgper mL per hour (37° C. in PBS). After around 16 hours, the solutionbecomes saturated with the drug and drug release is greatly retardeduntil the solution is refreshed.

Furthermore, recent experiments suggest that the shape of the polymermay play a role in drug elution behavior, especially at later stages. Itwas observed that the drug was released from the polymer beginning atthe outer layers. As the outer layers become depleted, the remainingdrug at the center of the polymer was observed to elute at a slightlyslower rate.

Example 12 General Procedure for the Preparation of PolymerizablePre-Formulations

Several representative formulations for both sticky and non-sticky filmsare listed in Table 10 along with specific reaction details. The filmshad thicknesses ranging from 100 to 500 μm, and may be layered withdifferent formulations in a composite film.

TABLE 10 (A) Summary of the reaction details for several representativethin film formulations; (B) more detailed tabulation of a selection ofthe reaction details including moles films ranged in thickness from 100to 500 μm). (A) Amine/Ester % Components Molar Ratio Buffer Solution4ARM-20k-AA & 8ARM-15k-SG 1 0.15M 19.6 phosphate, pH 7.99 4ARM-5k-NH2 &4ARM-10k-SG 4.5/1   0.05M 39 phosphate, pH 7.40 4ARM-5k-NH2 &4ARM-10k-SG 1 0.05M 36.4 phosphate, pH 7.40 4ARM-5k-NH2 & 4ARM-10k-SG &HPMC (1.25%) 4.5/1   0.10M 39 phosphate, pH 7.80 4ARM-2k-NH2 &4ARM-10k-SG & HPMC (1.5%) 8/1 0.10M 30.6 phosphate, pH 7.80 4ARM-2k-NH2& 4ARM-20k-SGA & MC (2%) 8/1 0.15M 30 phosphate, pH 7.94 4ARM-2k-NH2 &4ARM-20k-SGA & MC (2%) 10/1  0.15M 30 phosphate, pH 7.94 (B) PolymerArms % Solution Components MW Mmoles Wt (g) Arm mmoles Eq (w/v)4ARM-20k-AA 20000 1000 0.2 4 0.01 0.04 8ARM-15k-SG 15000 1000 0.075 80.01 0.04 Buffer Volume (phosphate) 1.4 19.6 4ARM-5k-NH2 5000 1000 0.274 0.05 0.22 4ARM-10k-SG 10000 1000 0.12 4 0.01 0.05 Buffer Volume(phosphate) 1 39.0 4ARM-5k-NH2 5000 1000 0.17 4 0.03 0.14 4ARM-10k-SG10000 1000 0.34 4 0.03 0.14 Buffer Volume (phosphate) 1.4 36.44ARM-5k-NH2 5000 1000 0.27 4 0.05 0.22 4ARM-10k-SG 10000 1000 0.12 40.01 0.05 Buffer Volume (phosphate) 1 39.0 Viscosity Enhancer 1.25% HPMC

Example 13 Preparation of Kits and their Use

Several kits were prepared with polymer formulation tested earlier. Thematerials used to assemble the kits are listed in Table 11 and theformulations used are listed in Table 12. The kits are typicallycomposed of two syringes, one syringe containing the solid componentsand the other syringe containing the liquid buffer. The syringes areconnected via a mixing tube and a one-way valve. The contents of thesyringes are mixed via opening the valve and transferring the contentsof one syringe into the other, repeatedly, for 10 to 20 seconds. Thespent syringe and mixing tube are then removed and discarded, and theactive syringe is fitted with a dispensing unit, such as a needle orcannula, and the polymer solution is expelled until the onset ofgelation. In other embodiments, the viscous solution impedes thedissolution of the solid components and thus a third syringe isemployed. The third syringe contains a concentrated viscous buffer thatenhances the viscosity of the solution once all the components havedissolved. In some embodiments, the optical clarity of the resultingpolymer is improved through the addition of a syringe filter.

All of the formulations tested were easily dispensed through a 22 gaugeneedle. The mixing action between the two syringes was turbulent and theintroduction of a significant amount of air bubbles was apparent. Gentlemixing results in a clear material free of bubbles. Alternatively, theuse of a syringe filter was found to remove bubbles without any changein the polymer properties.

TABLE 11 Materials used to fabricate kits including vendor, part numberand lot number. Description Vendor Vincon Tubing, ⅛″ I.D. Ryan HercoFlow Solutions ¼″ O.D. 1/16″ wall, 100 Ft. 12 mL Luer-Lok Syringe TycoHealthcare, Kendall Monoject ™ 3 mL Luer-Lok Syringe Tyco Healthcare,Kendall Monoject ™ One Way Stopcock, Female QOSINA Luer Lock to MaleLuer Female Luer Lock Barb QOSINA for ⅛″ I.D. tubing, RSPC Non-ventedLuer Dispensor QOSINA Tip Cap, White 32 mm Hydrophilic Syringe PALL ®Life Sciences Filter, 5 micron

TABLE 12 The detailed contents for four different kits; the solidcomponents are in one syringe, while the liquid components are inanother syringe; a mixing tube connects the two syringes. Components MWwt (g) Arm mmoles Arms Eq % Solution 8ARM-20k-NH2 20000 0.04 8 0.0020.016 4ARM-20k-SGA 20000 0.08 4 0.004 0.016 Phosphate buffer 2.5 mL0.10M, pH 7.80 4.8 Viscosity Enhancer No viscosity enhancer 8ARM-20k-NH220000 0.04 8 0.002 0.016 4ARM-20k-SGA 20000 0.08 4 0.004 0.016 Phosphatebuffer 2.5 mL 0.10M, pH 7.80 4.8 Viscosity Enhancer 0.3% HPMC8ARM-20k-NH2 20000 0.04 8 0.002 0.016 4ARM-20k-SGA 20000 0.08 4 0.0040.016 Phosphate buffer 2.5 mL 0.10M, pH 7.80 4.8 Viscosity Enhancer 7.5%Povidone 8ARM-20k-NH2 20000 0.04 8 0.002 0.016 4ARM-20k-SGA 20000 0.08 40.004 0.016 Phosphate buffer 2.5 mL 0.10M, pH 7.80 4.8 ViscosityEnhancer 1.0% HPMC

Several additional kits were prepared with the polymer formulation thatperformed the best in initial trials. The materials used to assemble thekits are listed in Table 13. The kits are typically composed of twosyringes, one syringe containing the solid components and the othersyringe containing the liquid buffer. The syringes were loaded byremoving the plungers, adding the components, purging the syringe with agentle flow of nitrogen gas for 20 seconds, and then replacing theplunger. Finally, the plungers were depressed as much as possible toreduce the internal volume of the syringes. The specifications for theamounts of chemical components in the kits are listed in Table 14A. Asummary describing the lots of kits prepared is listed in Table 14B.

The syringes were connected directly after uncapping, the male partlocking into the female part. The contents of the syringes were mixedvia transferring the contents of one syringe into the other, repeatedly,for 10 to 20 seconds. The spent syringe was then removed and discarded,and the active syringe was fitted with a dispensing unit, such as aneedle or cannula, and the polymer solution was expelled until the onsetof gelation. In other embodiments, the viscous solution impeded thedissolution of the solid components and thus a third syringe wasemployed. The third syringe contained a concentrated viscous buffer thatenhanced the viscosity of the solution once all the components haddissolved.

All the formulations tested were easily dispensed through a 22 gaugeneedle. The mixing action between the two syringes was turbulent and theintroduction of a significant amount of air bubbles was apparent. Theuse of a syringe filter was found to remove bubbles without any changein the polymer properties.

The prepared kits were placed into foil pouches along with one oxygenabsorbing packet per pouch. The pouches were heat sealed with a CHTC-280PROMAX tabletop chamber sealing unit. Two different modes of sealingwere explored: under nitrogen and under vacuum. The settings for sealingunder nitrogen were: 30 seconds of vacuum, 20 seconds of nitrogen, 1.5seconds of heat sealing, and 3.0 seconds of cooling. The settings forsealing under vacuum were: 60 seconds of vacuum, 0 seconds of nitrogen,1.5 seconds of heat sealing, and 3.0 seconds of cooling.

TABLE 13 Materials used to fabricate kits including vendor, part numberand lot number. Description Vendor 12 mL Male Luer-Lok Syringe TycoHealthcare, Kendall Monoject ™ 5 mL Female Luer Lock QOSINA Syringe,Purple Male Luer Lock Cap, Non- QOSINA vented Female Non-vented LuerQOSINA Dispensor Tip Cap, White 100 cc oxygen absorbing packet IMPAK6.25″ × 9″ OD IMPAK PAKVF4 Mylar foil pouch

TABLE 14 Specifications for kit components for the8ARM-20k-AA/8ARM-20-NH2 & 4ARM-20k- SGA formulation with 60, 65, 70 and75% degradable amine (A). LOT formulation summary (B). (A)Specifications Components 60/40 65/35 70/30 75/25 8ARM-20k-AA0.024-0.026 g 0.026-0.027 g 0.028-0.029 g 0.030-0.031 g 8ARM-20k-NH20.014-0.016 g 0.013-0.014 g 0.011-0.012 g 0.009-0.010 g 4ARM-20k-SGA0.080-0.082 g 0.080-0.082 g 0.080-0.082 g 0.080-0.082 g Phosphate Buffer2.50 mL of 0.10M phosphate, pH 7.58, 0.30% HPMC (8.48 cSt +/− 0.06 @ 20°C.) (B) Formulation Buffer pH Sealing Method Notes 60/40 7.46 nitrogen60/40 7.58 nitrogen 60/40 7.72 nitrogen 70/30 7.58 vacuum 70/30 7.58vacuum no nitrogen purging of syringe 65/35 7.58 vacuum 75/25 7.58vacuum 75/25 7.58 vacuum 75/25 7.58 nitrogen 65/35 7.58 vacuum 65/357.58 nitrogen

Several kits were prepared for use in beta testing. The materials usedto assemble the kits are listed in Table 15. The kits are typicallycomposed of two syringes, one syringe containing the solid componentsand the other syringe containing the liquid buffer. The syringes wereloaded by removing the plungers, adding the components, purging thesyringe with a gentle flow of inert gas for 10 seconds, and thenreplacing the plunger. Finally, the plungers were depressed as much aspossible to reduce the internal volume of the syringes.

Alternatively, a single syringe kit may be prepared by loading the solidcomponents into one female syringe along with a solid form of thephosphate buffer. The kit is then utilized in a similar fashion as thedual syringe kit, except the user may use a specified amount of avariety of liquids in a male syringe. Typically, any substance providedin a liquid solution for injection may be used. Some examples ofsuitable liquids are water, saline, Kenalog-10, Depo-Medrol andNolvasan.

The kits are utilized in the following fashion. The syringes areconnected directly after uncapping, the male part locking into thefemale part. The contents of the syringes are mixed via transferring thecontents of one syringe into the other, repeatedly, for 10 to 20seconds. The spent syringe is then removed and discarded, and the activesyringe is fitted with a dispensing unit, such as a needle, a spraynozzle or a brush tip, and the polymer solution is expelled until theonset of gelation.

The prepared kits were placed into foil pouches along with one oxygenabsorbing packet and one indicating silica gel packet per pouch. Labelswere affixed to the pouches that displayed the product and company name,contact information, LOT and batch numbers, expiration date, andrecommended storage conditions. A radiation sterilization indicator thatchanges color from yellow to red upon exposure to sterilizing radiationwas also affixed to the upper left corner of the pouch. The pouches wereheat sealed with a CHTC-280 PROMAX tabletop chamber sealing unit. Thesettings for sealing under vacuum were: 50 seconds of vacuum, 1.5seconds of heat sealing, and 5.0 seconds of cooling.

An example detailing the lots of sterile kits prepared is listed inTable 16. A previous study found that if the loaded syringe was notpurged with nitrogen before replacing the plunger during kitpreparation, the sterile kits exhibited an increase in gel time of about30 seconds relative to kits that had syringes flushed with nitrogen. Nosignificant difference was found between kits that had been sealed undervacuum and kits that had been sealed under nitrogen. It was easilyobservable when the vacuum-sealed kits lost their seal, so it wasdecided to vacuum-seal all kits as standard procedure. The effects ofincluding the oxygen absorbing packet and silica gel packet to the kitson the long term storage stability is currently under investigation.

TABLE 15 Materials used to fabricate kits including vendor, and partnumber. Description Vendor Part # 10 mL Luer-Lok Syringe BD 309604Non-Vented Luer Dispenser Tip Cap, QOSINA 65119 White 5 mL FemaleLuer-Lock Syringe, QOSINA C3610 Purple PP Male Luer Lock Cap,Non-Vented, PP QOSINA  11166 Brush tip Flumatic BT01225R 5.25″ × 8″PAKVF4D Mylar foil pouch IMPAK 0525MFDFZ08TE 3.5″ × 6.5″ PAKVF4W Mylarfoil IMPAK 035MFW065Z pouch Radiation Sterilization Indicator QOSINA 13124 100 cc oxygen absorbing packet IMPAK OAP100 Indicating silica gelIMPAK 40ISG37

TABLE 16 Example specifications for kit components for the 8-arm-AA-20K/8- arm-NH2-20K & 4- arm-SGA-20K formulation with 75% degradableamine (A). LOT formulation summary (B). Components LOT# & Specifications(A) 8ARM-20k-AA 0.029-0.031 g 8ARM-20k-NH2 0.009-0.011 g 4ARM-20k-SGA0.079-0.081 g Phosphate Buffer 2.50 mL of 0.10M phosphate, pH 7.58,0.30% HPMC (8.48 cSt +/− 0.06 @ 20° C.) LOT Size 3 30 34 48 Gel Time (s)110-125 Degradation Time 10-12 (days) (B) 8ARM-20k-AA 0.029-0.031 g8ARM-20k-NH2 0.009-0.011 g 4ARM-20k-SGA 0.079-0.081 g Phosphate Buffer 0.03-0.06 g Powder Nolvasan (2% 2.50 mL, 1% denatonium chlorhexidine)benzoate LOT Size 64 Gel Time (s) 150  Degradation Time 11 (days)

The kit preparation time was recorded. Loading one buffer syringe tookan average of 1.5 minutes, while one solids syringe took an average of 4minutes. Vacuum sealing one kit took approximately 1.5 minutes. Thus,the time estimate for the preparation of one kit was 7 minutes, orapproximately 8 kits per hour. The kit preparation time may be improvedby premixing all the solids in the correct ratios such that only onemass of solids needs to be measured, and by optimizing the vacuumsealing procedure by reducing the vacuum cycle time.

All the formulations tested were easily dispensed through a 23 to 34gauge needle. Higher gauges exhibit a lower flow rate as expected. Themixing action between the two syringes was turbulent and theintroduction of a significant amount of air bubbles was apparent. Theuse of a syringe filter was found to remove bubbles without any changein the polymer properties.

For the single syringe system, the effect of phosphate powder use wasinvestigated. FIG. 19 shows the effect of varying amounts orconcentrations of the solid phosphate on polymer gel times and solutionpH. The system was found to be relatively insensitive to the amount ofphosphate, tolerating up to 2-fold differences without significantvariation.

Kit Sterilization & Testing

The sealed kits were packed into large sized FedEx boxes. Each box wassterilized via electron-beam radiation at NUTEK Corporation according toa standard procedure that was developed. Included in this report is acopy of the standard sterilization procedure document.

For each lot of sterilized kits, a gel time and degradation time testwas performed on a randomly selected kit to verify the viability of thematerials. A previous study included a runner or control box of kitsthat was not sterilized, and concluded that environmental conditionsduring transit of the kits did not play a significant role in gel timechanges.

Sterilized kits were sent to NAMSA for sterility verification accordingto USP<71>. The kits were verified as sterile.

No physical changes in the monomer and phosphate buffer solutions wereobserved post-sterilization. Prior experiments have shown that thepolymer gel times consistently increase by approximately 30 secondsafter sterilization. For example, a polymer with a 90 second gel timewill exhibit a 120 second gel time after sterilization. The pH of thesterile buffer was unchanged, so it was suspected that some monomerdegradation during sterilization occurred. This was confirmed bypreparing unsterilized polymers at various concentrations and comparingthe gel times, degradation times and mechanical properties withsterilized polymers (FIG. 20). The current data shows that the monomersexperience roughly 15 to 20% degradation upon sterilization. Thus, a 5%polymer after sterilization will behave similarly to a 4% polymer.Additional experiments are planned to establish a detailed qualitycontrol calibration curve.

Storage Stability

The sterilized kits were stored at 5° C. Some kits were stored at 20° C.or 37° C. to explore the effect of temperature on storage stability. Thestability of the kits was primarily quantified by recording changes ingel time, which is directly proportional to the extent of monomerdegradation. The 37° C. temperature was maintained by submerging thekits fully into the water bath and thus represents the worst casescenario regarding humidity.

The storage stability of the kits was explored by placing some kits at5° C., 20° C. or 37° C. and measuring the change in gel times at definedintervals. The kits were prepared and sealed according to the proceduresdetailed in a previous section. The results are shown in FIG. 21. Over16 weeks, no significant change in gel times were observed for kitsstored at 5° C. and 20° C. At 37° C., the gel time begins to increaseafter roughly 1 week at a constant rate. The foil pouch proved to be aneffective moisture barrier. The indicating silica gel packet exhibitedonly mild signs of moisture absorption as evidenced by the color. Longerterm data is still in the process of being collected.

Example 13A Example of Syringe Kit Preparation

One syringe kit was developed where the components are stored in twosyringes, a male and a female syringe. The female syringe contains amixture of white powders. The male syringe contains a buffer solution.The two syringes are connected and the contents mixed to produce aliquid polymer. The liquid polymer is then sprayed or applied over thesuture wound where it covers the entire suture line. During the process,the polymer enters the voids left by sutures and protects the wound frominfections. At the wound site, the liquid polymer turns into a solid geland stays at the site for over two weeks. During this time, the wound ishealed and infection free.

The components necessary to prepare the kit are disclosed in Table 17and Table 18. To prepare the powder components of the kit to fill intothe female syringe, the plunger of the 5 mL female Luer-lock syringe wasremoved, and the syringe was capped with the appropriate cap.8ARM-20k-AA (0.028 g, the acceptable weight range is 0.0270 g to 0.0300g), 8ARM-20k-NH2 (0.012 g, the acceptable weight range is 0.0100 g to0.0130 g), 4ARM-20k-SGA (0.080 g, the acceptable weight range is 0.0790g to 0.0820 g), and 0.043 g of freeze-dried phosphate buffer powder(0.043 g, the acceptable weight range is 0.035 g to 0.052 g) were eachcarefully weighed out and poured into the syringe. The syringe was thenflushed nitrogen/argon gas for about 10 seconds at a rate of 5 to 10L/min and the plunger was replaced to seal the contents. The syringe wasthen flipped so that the cap was facing towards the ceiling. The syringecap was then loosened and the air space in the syringe was minimized byexpelling as much air as possible from the syringe. Typical compressedpowder volume is 0.2 mL. Then, the syringe cap was tighten until the capwas finger tight.

The liquid component was prepared on a 500 mL batch size, wherein 50 mLof commercial 2% chlohexidine solution, 450 mL of distilled water, and1.5 g of HPMC were poured in to sterile container. The sterile containerwas then capped and shook vigorously for 10 seconds. The solution wasallowed to stand under ambient conditions for 16 hours, thereby allowingfor the foam to dissipate and any remaining HPMC to dissolve.

The liquid/buffer syringe was prepared by removing the plunger of themale Luer-lock syringe followed by capping the syringe with theappropriate cap. 2.50 mL of the buffer/liquid solution was transfered bypipette into the syringe. Mixing the liquid and solid componentstogether will afford a 0.1 M phosphate buffer solution at pH 7.4. Thesyringe was then flushed with nitrogen/argon gas for about 5 seconds ata rate of 5 to 10 L/min. The plunger of the syringe was then replaced toseal the contents. Then the syringe was flipped so that the cap wasfacing towards the ceiling and the syringe cap was loosen and air spacewas minimized by expelling as much air as possible from the syringe.Then the syringe cap was tightened until the cap was finger tight. Aconfiguration of this kit embodiment is shown in Table 19 (Configuration1).

Alternately, another embodiment of the kit is where the solid componentsare 8-ARM-20k-AA (0.028 g), 8-ARM-20k-NH2 (0.012 g), and 4 ARM-20k-SGA(0.080 g) (Configuration 2, Table 20). The liquid component is comprisedof 2.50 mL of 0.1 M phosphate buffer with 0.3% HPMC. In a furtherembodiment of the kit, the solid components are comprised of8-ARM-20k-AA (0.0112 g), 8-ARM-20k-NH2 (0.0056 g), 4 ARM-20k-SGA (0.032g), and phosphate solid buffer/HPMC powder (0.017 g) (Configuration 3,Table 21). For this formulation, 1.0 mL of liquid is used, wherein theliquid component can be saline, DI water, or therapeutic agent.

TABLE 17 Components used to fabricate the solid components for thefemale syringe Components Technical Name 8ARM-20k-AA 8ARM PEG Acetateamine, HCl salt, MW 20k 8ARM-20k- 8ARM PEG amine NH2 (hexaglycerol), HClsalt, MW 20k 4ARM-20k- 4-arm PEG succinimidyl SGA glutaramide(pentaerythritol), MW 20k Commercial 2% chlorhexidine solutionFreeze-dried phosphate buffer powder

TABLE 18 Materials used to fabricate kit including vendor, part numberand lot number. Vendor Description Vendor Part # Catalog # 10 mLLuer-Lok Syringe BD CM-0003 309604 Non-Vented Luer Dispenser Tip Cap,QOSINA CM-0004  65119 White 5 mL Female Luer-Lock Syringe, QOSINACM-0005 C3610 Purple PP Male Luer Lock Cap, Non-Vented, QOSINA CM-0006 11166 PP

TABLE 19 Exemplary Kit Configuration 1. Kit Configuration 1 Syringe 1Syringe 2 (solids) (Liquid) Brush Components 5 cc Female 5 cc MaleHolder 8-ARM-20k-AA (Powder) 0.028 g 8-ARM-20k-NH2 (Powder) 0.012 g4-ARM-20k-SGA (Powder) 0.080 g Phosphate Buffer (Powder) 0.043 g ViscousAntiseptic Solution 0.3% 2.50 mL HPMC (hyrdoxy propyl methyl cellulose)Brush Tip 1 Brush Tip

TABLE 20 Exemplary Kit Configuration 2. Kit Configuration 2 Syringe 1Syringe 2 (solids) (Liquid) Brush Components 5 cc Female 5 cc MaleContainer 8-ARM-20k-AA (Powder) 0.028 g 8-ARM-20k-NH2 (Powder) 0.012 g4-ARM-20k-SGA (Powder) 0.080 g 0.1M Phosphate buffer with 0.3% 2.50 mLHPMC (hyrdoxy propyl methyl cellulose) Brush Tip 1 Brush Tip

TABLE 21 Exemplary Kit Configuration 3. Kit Configuration 3 Syringe 1Syringe 2 (solids) (empty) Brush Components 5 cc Female 5 cc MaleContainer 8-ARM-20k-AA 0.0112 g 8-ARM-20k-NH2 0.0056 g 4-ARM-20k-SGA 0.032 g Phosphate Buffer/HPMC Powder  0.017 g Brush Tip 1 Brush Tip

Example 13B Example of Syringe Kit Preparation

Another syringe kit was developed where the solid components, a mixtureof white powders, are stored in one female syringe. A standard malesyringe is used to take up the drug solution, such as one containingKenalog. The two syringes are connected and the contents mixed toproduce a liquid polymer. The liquid polymer is then delivered to thetarget site.

The components necessary to prepare the kit are disclosed in Table 17and Table 18. To prepare the powder components of the kit to fill intothe female syringe, the plunger of the 5 mL female Luer-lock syringe wasremoved, and the syringe was capped with the appropriate cap.8ARM-20k-AA (0.0125 g, the acceptable weight range is 0.012 g to 0.013g), 8ARM-20k-NH2 (0.075 g, the acceptable weight range is 0.007 g to0.008 g), 4ARM-20k-SGA (0.040 g, the acceptable weight range is 0.040 gto 0.042 g), and 0.018 g of freeze-dried phosphate buffer powder (0.043g, the acceptable weight range is 0.017 g to 0.022 g) were eachcarefully weighed out and poured into the syringe. The syringe was thenflushed nitrogen/argon gas for about 10 seconds at a rate of 5 to 10L/min and the plunger was replaced to seal the contents. The syringe wasthen flipped so that the cap was facing towards the ceiling. The syringecap was then loosened and the air space in the syringe was minimized byexpelling as much air as possible from the syringe. Then, the syringecap was tightened until the cap was finger tight.

The liquid component for this embodiment is designed to be 1.0 mL ofsaline, DI water, or therapeutic agent, wherein mixing the contents ofthe two syringes together yields a 0.1 M phosphate buffer solution at apH of 7.4.

Furthermore, the degradation time of the exemplified biocompatiblehydrogel polymers can be controlled by adjusting the solutionconcentration, monomer type, and monomer amounts. 70% Acetate Amine hasa degradation time of approximately 14 days while 62.5% Acetate Aminehas a degradation time of approximately 180 days.

Example 14 Clinical Studies of Hydrogel Polymer on Wound Healing withCreated Wounds

To test the effectivness of the biocompatible hydrogel polymer ofExample 13A to seal incisions post operatively and thereby decreasingthe chances of post operative infections, a clinical study was performedunder controlled settings wherein the horses used had incisions orlacerations that were specifically created in a clinical setting. Onehorse was used for experimental protocol and 9 clinical horses hadcreated incisions or lacerations.

The experimental protocol horse was used to determine the safety andeffectiveness of the biocompatible hydrogel polymer. A three year old,quarter horse, mare was used for the experimental protocol. Both sidesof the neck were clipped and sterilely prepared. She was given 150 mg ofxylazine for sedation. Twenty mls of lidocaine was used to locally toblock the skin in 2 parallel lines (10 mls per site) on each side of theneck. Four incisions were made through the skin. The two incisions onthe right side were closed with staples and the cranial incision wassealed with the polymer. The two incisions on the left side were closedwith 2-0 prolene in a cruciate pattern. The cranial incision was sealedwith the polymer. The horse was monitored for the next 14 days. Theincisions were inspected daily for any heat, pain, swelling ordischarge. A 4 mm punch biopsy was taken at day 15 when the sutures andstaples were removed.

The 9 other horses were clinical cases presented for surgical proceduresor lacerations due to trauma. Three horses were presented for colic andthe other six was seen for lacerations due to trauma. All of theclinical horses followed the same routine for post operative care. Thecolics were treated with antibiotics (3 days) and NSAID's (10 days). Thelacerations were cleaned and the hair removed from the site. The sitewas cleaned as well as possible with saline and debridement. Localanesthetic was placed along the wound edges and the lacerations wereclosed with sutures and or staples. All six horses only received NSAID'sfor 5-7 days and no antibiotics.

There was no histological difference seen from the biopsies on theexperimental horse between the covered sutured line and the uncoveredsutured line. Thus, the hydrogel polymer was safe and effective for usein the horse. The clinical horses healed with a few complications. Twoof the three colics experienced an increase in abdominal fluid formationor deposition, which is inevitable in certain colics. However, thisproblem can be addressed by strengthening the hydrogel polymer orapplying a wider application of the polymer to cover the incision site.For the laceration horses, the hydrogel polymer sealed the lacerationswith a 66.7% success rate initially without the use of systemicantibiotics. Two of the six laceration horses developed discharge, whichwas resolved with systemic antibiotics. With the use of antibiotics,there was a 100% recovery rate and the lacerations healed withoutcomplications. Thus, this clinical study demonstrates that thebiocompatible hydrogel polymer is effective for use in wound healing inhorses.

Example 15 Clinical Studies of Hydrogel Polymer for Wound Healing inReal Life Settings

Another clinical study to test of the effectiveness of the hydrogelpolymer on wound healing was performed on larger sample size of 100horses and wherein the horses had wounds that were not created inclinical setting (wounds received from real-life settings). Thebiocompatible hydrogel polymer was prepared as described in Example 13Afrom a mixture of 8ARM-20k-AA, 8-ARM-20k-NH2, and 4-ARM-20k-SGA anddissolved in phosphate buffered saline. Before the hydrogel polymergelled, the polymer was applied over over the wound with a brush tipapplicator. The hydrogel polymer gelled in about 90 seconds and coveredthe wound and wound edges.

On 54 horses, the biocompatible hydrogel polymer was applied over areason the body that were sutured from laceration repairs, mass removals,and elective surgeries. No bandages were used on 19 of the 54 horses(35%) and bandages were used on the remaining 35 horses (65%). Thebandages were used to prevent excessive swelling and were placed overthe wound site. Of the 35 horses that received bandages, 30 received aprimary bandage layer over the wound and the remaining 5 received aprimary bandage layer on top of the hydrogel polymer.

29 horses had the hydrogel polymer of placed on ventral midlineincisions (27 for colic surgeries, 1 for umbilical hernia repair, and 1for bladder stone removal). The horses recovered in a 16′×16′ recoverystall with head and tail ropes to assist in recovery. All of theincisions were examined daily for the next 14 days for any excessiveheat, pain, swelling or discharge. Two horses had abdominal bandagesplaced during the recovery period. Only 24 were available for long termevaluation. Five of the horses were euthanized prior to discharge.

Nine horses had the hydrogel polymer of placed for primary wound care.Three of the wounds (33%) were in areas too difficult to bandage or inan area where bandages are not used. Six of the nine horses (67%) hadwounds that were bandaged for compression. No primary bandage layer wasused over the wound.

Eight horses had the hydrogel polymer placed in the inguinal area forcryptorchid surgery with scrotal ablation. None of these 8 horses werebandaged. The mild swelling associated with the procedure was managedwith oral phenylbutazone at 2.2 mg/kg orally every 12 hours for 10 days.All the horses were placed on sulfamethoxazole/trimethoprin doublestrength (960 mg) dosed at 15 mg/kg orally given twice a day for only 5days.

All the owners were contacted about 30 days after the surgery or injuryto determine the satisfaction of the type of repair and anycomplications or comments associated with the hydrogel polymer.

Results

The largest group of 54 horses had the hydrogel polymer of coversurgically created or traumatically created wounds that were sutured.All the wounds healed without dehiscence or infection. For the horseswith bandages, the hydrogel polymer did not interfere with theapplication or function of the bandages. The majority of clients in thisgroup (48/54, 89%) were generally satisfied with the appearance of thehealed wound and healing process. The remaining clients (6/54, 11%) werenot completely satisfied with the results due to reasons that were notrelated to hydrogel polymer or hydrogel polymer performance.

In the group of 29 horses that had hydrogel polymer of cover ventralmidline incisions, 24 horses were available for long term evaluation and5 horses were euthanized for reasons not related to wound healing. Allthe owners were satisfied with the healing of the incisions. Themajority of the wounds had no evidence of complications. However, onehorse did develop slight drainage from the incision line, but this couldbe attributed to that fact that this horse had 18 feet of smallintestine removed and a large amount of saline was placed into theabdominal cavity prior to closing the incision. For this one horse, theincision line did appear to be infected and dehiscence of the skin didoccur. However, prior to placement of a new abdominal bandage, morehydrogel polymer was placed over the opened incision; and the horsehealed without any other complications. For the five horses that did notsurvive to discharge, one horse immediately developed myopathy postoperatively and was humanely euthanized. Three of the horses wereeuthanized due to continuous reflux for 5-7 days. The last horse waseuthanized due to early signs of laminitis.

For the 9 horses that were treated with the hydrogel polymer for primarywound care, 6 horses had habronemiasis, one had a dehisced wound, andthe other two had mass removals that could not be closed by primaryclosure. The 6 horses that were treated for habronemiasis had theirwounds injected with triamcinolone, covered with the hydrogel polymer,and bandaged to add compression to the wound. The other three woundswere on the elbow (surgically removed shoe boil), and squamous cellcarcinoma removal on the sheath and vaginal area. 5 of the 9 (56%) ofthe owners were satisfied with the results after a single injection of acorticosteroid, coverage with the hydrogel polymer followed by bandages.4 of the 9 (44%) of the owners were not happy with the results of thesteroid injection and the covering of the area. All four horses had thesites injected 3 more times every 2 weeks, and the last time aintralesional injection was done with the hydrogel polymer mixed withtriamcinolone (20 mg) followed by coverage with the hydrogelpolymer/triamcinolone mix. The 4 owners felt that the last injectionwith hydrogel polymer/triamcinolone mix helped the area heal better thanjust the steroid injections alone.

The 8 horses that had the scrotal ablation/cryptorchid surgery had nocomplications associated with the hydrogel polymer covering the incisionlines. All the owners of the 8 horses were very satisfied with theresults of the procedures, and no drainage or excessive pain was noticedby the owner or trainer.

Discussion

In this clinical study, the hydrogel polymer was used on 100 horses tocover a wide variety of wounds in various locations and on woundsreceived from actual real-life settings. The hydrogel polymer was usedon sutured, non-sutured, bandaged, and unbandaged wounds. The hydrogelpolymer was easy to apply and appeared to provide protection to the sitewhere applied. Furthermore, the hydrogel polymer did not interfere withbandaging of wounds, and in some instances, allowed for omission of theprimary bandage layer. Furthermore, the hydrogel polymer did not appearto cause any wound irritation or delay in wound healing.

The overall response by the owners was very favorable. Out of the 94horses used in the study, there were only 11 owners dissatisfied withthe overall outcome of the procedure (8.73%), and none of thedissatisfaction was due to the use of hydrogel polymer. In fact, 6 ofthe complaints were related to the burden of bandaging, a problem thatcan be addressed by the hydrogel polymer. The results of this studyhighlight the utility of the hydrogel polymer in wound healing on horsesin a variety of real-life settings and highlight the advantages of usingthe hydrogel polymer for wound healing. Applying the hydrogel polymer onthe incision site may benefit horses to heal with and without a bandage.Previous studies have shown that the recovery room floor is a primarysource of infection to a surgical site. The horse may recover betterwithout the added irritation of a bandage or stent placed over thesurgical site. The bandage can be placed after recovery to ensure goodplacement of the bandage if desired. Also, the hydrogel polymer can beused to cover sites that cannot be bandaged either due to location ortype of wound.

Example 16 Pathology Studies of Hydrogel Polymer in Horses

To evaluate the biocompatibility and safety of the hydrogel polymer foruse in horses, the local tissue response to hydrogel polymer wasevaluated.

Ten adult quarter horses ranging from 3-19 years of age with a mean ageof 11 years old were examined. The horses were not lame at a walk.Horses were fasted and injectable anesthesia(xylazine/ketamine/diazepam) was performed to allow easy placement ofthe hydrogel polymer of Example 13B. The hydrogel was placed into thefollowing sites: intra-vitreal, intra-articular (tarsometatarsal joint),intramuscular, intra-bursal (navicular bursa), intra-peritoneal,intra,-pleural, and subcuetaneousely via aseptic techniques. The horseswere examined daily for fever, lameness or any signs of discomfort. Thehorses were grouped into 5 groups of 2 horses. They were sacrificed atdays 3, 5, 7, 14, and 21 days. A complete post mortem exam was performedalong with histological examination of the tissues where the hydrogelpolymer was injected.

All the carcasses were in good nutritional condition, well fleshed andwith adequate fat reserves. Necropsy was performed and abnormalitieswere recorded. The histological examination of the tissues revealed thatonly minimal reactions were observed in tissues such as eyes, muscle,subcutaneous tissue and joints. Particularly, no gross abnormalitieswere found in the left tarsometatarsal joint, left front navicular bursain all of the horses examined. No lesions were found in the right eye orin the left subcutaneous sites in all of the horses examined. 70% of thehorses had no lesions in the left eye and 50% of the horses had nolesions in the left intramuscular region. Furthermore, it is worthnoting that all horses after the procedure had no problems standingafter recovering from the procedure. Thus, these studies show that nodetrimental inflammatory response was observed with the hydrogel polymerwas injected into different areas of the horse body.

Example 17 Clinical Evaluation of Hydrogel Polymer for Treating Lamenessin Horses

In this study, the effective of the hydrogel polymer as a drug deliverysystem was tested in 11 horses with palmar foot pain, which is a commoncause of lameness in performance horses. The pain associated within thepalmar aspect of the foot can be caused by pathologies of the boneand/or soft tissues located in the caudal heel of the horse. Theresponse to medical treatment of caudal heel pain varies and thestandard medical treatment for horses with caudal heel pain consist ofthe use of an oral non steroidal antinflammatory drugs, shoeing changes,stall rest, bisphosphonate (Tiludronate) or intrathecal injections of acorticosteroid with or without hyaluronic acid either into the distalinterphalangeal joint or the navicular bursa. Injections into thenavicular bursae can be technically difficult and may requireradiographic equipment to ensure proper placement of the needle in tothe bursa. Due to the difficulties of the intra-bursal injections,studies have evaluated the concentrations of corticosteroid that willdiffuse into the navicular bursa from the distal interphalangeal joint.

The use of intrathecal injections has been one of the primary ways totreat horses with caudal heel pain; however the products used within thespace are limited to their pharmacokinetics. The purpose of thisclinical study was to evaluate the effectiveness of the hydrogel polymeras drug delivery system for introducing triamcinalone acetonide into thenavicular bursa of horses with caudal heel pain. Furthermore, the safetyof the hydrogel polymer was also evaluated by noting any secondarycomplication associated with the use of a corticosteroid.

The hydrogel polymer used for this study is as described in Example 13B;wherein the hydrogel polymer was derived from a solid pre-formulation of8ARM-20k-AA, 8-ARM-20k-NH2, and 4-ARM-20k-SGA and dissolved with 40 mgof triamcinalone acetonide (Kenalog 40). The hydrogel polymer wasinitially a liquid and then polymerized in 90 seconds after mixing andhad a degradation time of two weeks.

Elevens horse were evaluated for lameness and it was confirmed thatcaudal heel pain was the only cause of lameness by a complete responseto palmar digital nerve blocks. All horses had a prior diagnosis ofnavicular disease. All horses had to have little to no response tostandard treatments prior to inclusion of the study. None of the horsesinvolved in the study had a bilateral neurectomy or a single limbneurectomy. Eight quarter horses, two arabian, and one warm blood wereinvolved with the clinical study.

Each horse was sedated with detomidine hydrochloride at 0.005 mg/kg ivand a abaxial sesamoid block using mepericane was performed eitherbilaterally or unilateral on the affected limb. The area at the caudalheel was aseptically prepared using chlorhexadine scrub and alcohol. A22 ga 3.5 inch spinal needle was used to inject the hydrogel and steroidcombination. The bursa was injected either standing on a 4 inch block orup in a podoblock. In the standing position the needle was placed about0.5-1 cm proximal to the coronary band and advanced parallel to theground until the navicular bone was contacted. In the non weight baringsituation the needle was placed between the bulbs of the heel anddirectly perpendicular to the ground. Either technique was confirmedwith radiographic conformation. Once the needle was in the bursa, thehydrogel polymer and steroid mixture was prepared and injected into thenavicular bursa. A total volume of 1 ml was placed into the navicularbursa. After injection, the needle was removed and a small bandagedplaced over the injection site for 20 minutes. All horse were dischargedafter injection and follow up calls were done daily for the first 3days, then weekly for the first 8 weeks, and then every month until thehorse started to show signs of lameness.

The results of the study were very promising. No complications werenoted with the injection site, hydrogel polymer and/or with thecorticosteroid. Furthermore, 91% of the horses responded positively tothe treatment (10/11) and an average decrease in AAEP lameness scale by90% was observed after 6 weeks. These results highlight the ability ofthe hydrogel polymer as a drug delivery system to deliver corticosteroids as the horses in this study did not respond to conventionaltreatments and improved to almost full resolution of lameness aftertreatment with the hydrogel polymer/corticosteroid.

What is claimed is:
 1. A solid polyglycol-based, fully synthetic,pre-formulation, comprising: (a) at least one solid first compoundcomprising more than two nucleophilic groups; and (b) at least one solidsecond compound comprising more than two electrophilic groups whereinthe solid polyglycol-based, fully synthetic, pre-formulation polymerizesand/or gels to form a polyglycol-based, fully synthetic, biocompatiblehydrogel polymer after addition of a liquid component.
 2. The solidpolyglycol-based, fully synthetic, pre-formulation of claim 1, furthercomprising a solid buffer component.
 3. The solid polyglycol-based,fully synthetic, pre-formulation of claim 1, wherein the liquidcomponent comprises water, saline, a buffer, a therapeutic agent or acombination thereof.
 4. The solid polyglycol-based, fully synthetic,pre-formulation of claim 1, further comprising a viscosity enhancer. 5.The solid polyglycol-based, fully synthetic, pre-formulation of claim 1,wherein the nucleophilic group comprises a thiol or amino group.
 6. Thesolid polyglycol-based, fully synthetic, pre-formulation of claim 1,wherein the solid first compound is a MULTIARM (5k-50k) polyolderivative comprising polyglycol subunits and more than two nucleophilicgroups.
 7. The solid polyglycol-based, fully synthetic, pre-formulationof claim 1, wherein the electrophilic group comprises an epoxide,N-succinimidyl succinate, N-succinimidyl glutarate, N-succinimidylsuccinamide or N-succinimidyl glutaramide.
 8. The solid polyglyol-based,fully synthetic, pre-formulation of claim 1, wherein the solid secondcompound is a MULTIARM (5k-50k) polyol derivative comprising polyglycolsubunits and more than two electrophilic groups.
 9. The solidpolyglycol-based, fully synthetic pre-formulation of claim 1, whereinthe solid first compound is a MULTIARM-(5-50k)-SH, aMULTIARM-(5-50k)-NH2, a MULTIARM-(5-50k)-AA, or a combination thereof,and the second compound is a MULTIARM-(5-50k)-SG, aMULTIARM-(5-50k)-SGA, a MULTIARM-(5-50k)-SS, or a combination thereof.10. The solid polyglycol-based, fully synthetic pre-formulation of claim9, wherein the solid first 8ARM-20k-AA, or a combination thereof, andthe second compound is 4ARM-10k-SG, 8ARM-15k-SG, 4ARM-20k-SGA,4ARM-10k-SS, or a combination thereof.
 11. The solid polyglycol-basedpre-formulation of claim 10, wherein the solid first compound is8ARM-20k-NH2 and/or 8ARM-20k-AA, and the second compound is4ARM-20k-SGA.
 12. The solid polyglycol-based, fully synthetic,pre-formulation of claim 1, wherein the solid polyglycol-based, fullysynthetic, pre-formulation further comprises one or more therapeuticagents.
 13. The solid polyglycol-based, fully synthetic, pre-formulationof claim 12, wherein the therapeutic agent is selected from anantibacterial agent, an antifungal agent, an immunosuppressant agent, ananti-inflammatory agent, a bisphosphonate, gallium nitrate, stem cells,an antiseptic agent, and a lubricity agent.
 14. The solidpolyglycol-based, fully synthetic, pre-formulation of claim 13 whereinthe therapeutic agent is a lubricity agent.
 15. The solidpolyglycol-based, fully synthetic, pre-formulation of claim 14, whereinthe lubricity agent is hyaluronic acid.
 16. A method of treating woundsof a mammal by delivering a liquid polyglycol-based, fully synthetic,biocompatible formulation formed by adding a liquid component to thesolid polyglycol-based, fully synthetic, pre-formulation of claim 1 to atarget site of the wound of the mammal, wherein the liquidpolyglycol-based, fully synthetic, biocompatible formulation gels at thetarget site of the wound to form a polyglycol-based, fully synthetic,biocompatible hydrogel polymer.
 17. A method of treating arthritis in amammal by delivering a liquid polyglycol-based, fully synthetic,biocompatible formulation formed by adding a liquid component to a solidpolyglycol-based, fully synthetic, pre-formulation of claim 1 into atarget site in a joint space, wherein the liquid polyglycol-based, fullysynthetic, biocompatible formulation gels at the target site in thejoint space to form a polyglycol-based, fully synthetic, biocompatiblehydrogel polymer.
 18. A method of treating navicular disease in a horseby delivering a liquid polyglycol-based, fully synthetic, biocompatibleformulation formed by adding a liquid component to a solidpolyglycol-based, fully synthetic, pre-formulation of claim 1 to atarget site in a hoof of the horse, wherein the polyglycol-based, fullysynthetic, biocompatible formulation gels at the target site in the hoofof the horse to form a polyglycol-based, fully synthetic, biocompatiblehydrogel polymer.
 19. A method of claim 16, wherein the mammal is ahuman or an animal.
 20. The polyglycol-based, fully synthetic,biocompatible hydrogel polymer of claim 1.